diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index f3975df1270..04e94c0452f 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -279,14 +279,12 @@ function _block_get_renderable_region($list = array()) {
       }
     }
     else {
-      $key_components = explode('.', $key);
-      $id = array_pop($key_components);
       $build[$key] = array(
         '#block' => $block,
         '#weight' => $block->get('weight'),
         '#pre_render' => array('_block_get_renderable_block'),
         '#cache' => array(
-          'keys' => array($id, $settings['module']),
+          'keys' => array($key, $settings['module']),
           'granularity' => $settings['cache'],
           'bin' => 'block',
           'tags' => array('content' => TRUE),
@@ -383,9 +381,15 @@ function block_theme_initialize($theme) {
     $regions = system_region_list($theme, REGIONS_VISIBLE);
     $default_theme_blocks = entity_load_multiple_by_properties('block', array('theme' => $default_theme));
     foreach ($default_theme_blocks as $default_theme_block_id => $default_theme_block) {
-      list(, $machine_name) = explode('.', $default_theme_block_id);
+      if (strpos($default_theme_block_id, $default_theme . '_') === 0) {
+        $id = str_replace($default_theme, $theme, $default_theme_block_id);
+      }
+      else {
+        $id = $theme . '_' . $default_theme_block_id;
+      }
       $block = $default_theme_block->createDuplicate();
-      $block->set('id', $theme . '.' . $machine_name);
+      $block->set('id', $id);
+      $block->set('theme', $theme);
       // If the region isn't supported by the theme, assign the block to the
       // theme's default region.
       if (!isset($regions[$block->get('region')])) {
@@ -559,9 +563,7 @@ function template_preprocess_block(&$variables) {
 
   // Create a valid HTML ID and make sure it is unique.
   if ($id = $variables['elements']['#block']->id()) {
-    $config_id = explode('.', $id);
-    $machine_name = array_pop($config_id);
-    $variables['attributes']['id'] = drupal_html_id('block-' . $machine_name);
+    $variables['attributes']['id'] = drupal_html_id('block-' . $id);
   }
 }
 
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCreationTest.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCreationTest.php
index ff36e80f6cb..e94e2215100 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCreationTest.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockCreationTest.php
@@ -149,7 +149,7 @@ class CustomBlockCreationTest extends CustomBlockTestBase {
 
     // Place the block.
     $instance = array(
-      'machine_name' => drupal_strtolower($edit['info']),
+      'id' => drupal_strtolower($edit['info']),
       'settings[label]' => $edit['info'],
       'region' => 'sidebar_first',
     );
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockFieldTest.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockFieldTest.php
index c51be016f5e..54b5d6f7524 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockFieldTest.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockFieldTest.php
@@ -104,7 +104,7 @@ class CustomBlockFieldTest extends CustomBlockTestBase {
     $url = 'admin/structure/block/add/custom_block:' . $block->uuid() . '/' . \Drupal::config('system.theme')->get('default');
     // Place the block.
     $instance = array(
-      'machine_name' => drupal_strtolower($edit['info']),
+      'id' => drupal_strtolower($edit['info']),
       'settings[label]' => $edit['info'],
       'region' => 'sidebar_first',
     );
diff --git a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php
index 18e55df7111..ab67e9b2df8 100644
--- a/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php
+++ b/core/modules/block/custom_block/lib/Drupal/custom_block/Tests/CustomBlockTypeTest.php
@@ -186,7 +186,7 @@ class CustomBlockTypeTest extends CustomBlockTestBase {
           $destination = 'admin/structure/block/add/custom_block:' . $block->uuid() . '/' . $theme;
           $this->assertUrl(url($destination, array('absolute' => TRUE)));
           $this->drupalPostForm(NULL, array(), t('Save block'));
-          $this->assertUrl(url("admin/structure/block/list/$theme", array('absolute' => TRUE, 'query' => array('block-placement' => drupal_html_class($theme . '.' . $edit['info'])))));
+          $this->assertUrl(url("admin/structure/block/list/$theme", array('absolute' => TRUE, 'query' => array('block-placement' => drupal_html_class($edit['info'])))));
         }
         else {
           $this->fail('Could not load created block.');
diff --git a/core/modules/block/lib/Drupal/block/BlockFormController.php b/core/modules/block/lib/Drupal/block/BlockFormController.php
index 4a4d1fb9d0f..92d36966437 100644
--- a/core/modules/block/lib/Drupal/block/BlockFormController.php
+++ b/core/modules/block/lib/Drupal/block/BlockFormController.php
@@ -93,14 +93,10 @@ class BlockFormController extends EntityFormController {
   public function form(array $form, array &$form_state) {
     $entity = $this->entity;
     $form['#tree'] = TRUE;
-    $form['id'] = array(
-      '#type' => 'value',
-      '#value' => $entity->id(),
-    );
     $form['settings'] = $entity->getPlugin()->buildConfigurationForm(array(), $form_state);
 
     // If creating a new block, calculate a safe default machine name.
-    $form['machine_name'] = array(
+    $form['id'] = array(
       '#type' => 'machine_name',
       '#maxlength' => 64,
       '#description' => $this->t('A unique name for this block instance. Must be alpha-numeric and underscore separated.'),
@@ -294,15 +290,6 @@ class BlockFormController extends EntityFormController {
   public function validate(array $form, array &$form_state) {
     parent::validate($form, $form_state);
 
-    $entity = $this->entity;
-    if ($entity->isNew()) {
-      form_set_value($form['id'], $form_state['values']['theme'] . '.' . $form_state['values']['machine_name'], $form_state);
-    }
-    if (!empty($form['machine_name']['#disabled'])) {
-      // Get machine name from original value (without prepended theme name).
-      $config_id = explode('.', $form_state['values']['machine_name']);
-      $form_state['values']['machine_name'] = array_pop($config_id);
-    }
     // Remove empty lines from the role visibility list.
     $form_state['values']['visibility']['role']['roles'] = array_filter($form_state['values']['visibility']['role']['roles']);
     // The Block Entity form puts all block plugin form elements in the
@@ -311,7 +298,7 @@ class BlockFormController extends EntityFormController {
       'values' => &$form_state['values']['settings']
     );
     // Call the plugin validate handler.
-    $entity->getPlugin()->validateConfigurationForm($form, $settings);
+    $this->entity->getPlugin()->validateConfigurationForm($form, $settings);
   }
 
   /**
diff --git a/core/modules/block/lib/Drupal/block/Entity/Block.php b/core/modules/block/lib/Drupal/block/Entity/Block.php
index 7f5c895a178..67d10e41008 100644
--- a/core/modules/block/lib/Drupal/block/Entity/Block.php
+++ b/core/modules/block/lib/Drupal/block/Entity/Block.php
@@ -125,24 +125,13 @@ class Block extends ConfigEntityBase implements BlockInterface {
     return $settings['label'];
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function get($property_name) {
-    // The theme is stored in the entity ID.
-    $value = parent::get($property_name);
-    if ($property_name == 'theme' && !$value) {
-      list($value) = explode('.', $this->id());
-    }
-    return $value;
-  }
-
   /**
    * Overrides \Drupal\Core\Config\Entity\ConfigEntityBase::getExportProperties();
    */
   public function getExportProperties() {
     $properties = parent::getExportProperties();
     $names = array(
+      'theme',
       'region',
       'weight',
       'plugin',
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockHookOperationTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockHookOperationTest.php
index 3621f26fc0b..52120f14da7 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockHookOperationTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockHookOperationTest.php
@@ -48,13 +48,13 @@ class BlockHookOperationTest extends WebTestBase {
   public function testBlockOperationAlter() {
     // Add a test block, any block will do.
     // Set the machine name so the test_operation link can be built later.
-    $block_machine_name = Unicode::strtolower($this->randomName(16));
-    $this->drupalPlaceBlock('system_powered_by_block', array('machine_name' => $block_machine_name));
+    $block_id = Unicode::strtolower($this->randomName(16));
+    $this->drupalPlaceBlock('system_powered_by_block', array('id' => $block_id));
 
     // Get the Block listing.
     $this->drupalGet('admin/structure/block');
 
-    $test_operation_link = 'admin/structure/block/manage/stark.' . $block_machine_name . '/test_operation';
+    $test_operation_link = 'admin/structure/block/manage/' . $block_id . '/test_operation';
     // Test if the test_operation link is on the page.
     $this->assertLinkByHref($test_operation_link);
   }
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockHtmlIdTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockHtmlIdTest.php
index c719fbecc37..de18e91f6f1 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockHtmlIdTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockHtmlIdTest.php
@@ -40,7 +40,7 @@ class BlockHtmlIdTest extends WebTestBase {
 
     // Enable our test blocks.
     $this->drupalPlaceBlock('system_menu_block:tools');
-    $this->drupalPlaceBlock('test_html_id', array('machine_name' => 'test_id_block'));
+    $this->drupalPlaceBlock('test_html_id', array('id' => 'test_id_block'));
   }
 
   /**
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockLanguageTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockLanguageTest.php
index 915e4bb2cf4..2e4a4c6e5b6 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockLanguageTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockLanguageTest.php
@@ -62,7 +62,7 @@ class BlockLanguageTest extends WebTestBase {
     // Enable a standard block and set the visibility setting for one language.
     $edit = array(
       'visibility[language][langcodes][en]' => TRUE,
-      'machine_name' => strtolower($this->randomName(8)),
+      'id' => strtolower($this->randomName(8)),
       'region' => 'sidebar_first',
     );
     $this->drupalPostForm('admin/structure/block/add/system_powered_by_block' . '/' . $default_theme, $edit, t('Save block'));
@@ -99,7 +99,6 @@ class BlockLanguageTest extends WebTestBase {
           ),
         ),
       ),
-      'machine_name' => 'language_block_test',
     );
     $block = $this->drupalPlaceBlock('system_powered_by_block', $edit);
 
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockRenderOrderTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockRenderOrderTest.php
index f92e8500d76..da6202e9f58 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockRenderOrderTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockRenderOrderTest.php
@@ -45,17 +45,17 @@ class BlockRenderOrderTest extends WebTestBase {
     // Enable test blocks and place them in the same region.
     $region = 'header';
     $test_blocks = array(
-      'stark.powered' => array(
+      'stark_powered' => array(
         'weight' => '-3',
-        'machine_name' => 'powered',
+        'id' => 'stark_powered',
       ),
-      'stark.by' => array(
+      'stark_by' => array(
         'weight' => '3',
-        'machine_name' => 'by',
+        'id' => 'stark_by',
       ),
-      'stark.drupal' => array(
+      'stark_drupal' => array(
         'weight' => '3',
-        'machine_name' => 'drupal',
+        'id' => 'stark_drupal',
       ),
     );
 
@@ -65,7 +65,7 @@ class BlockRenderOrderTest extends WebTestBase {
         'label' => 'Test Block',
         'region' => $region,
         'weight' => $test_block['weight'],
-        'machine_name' => $test_block['machine_name'],
+        'id' => $test_block['id'],
       ));
     }
 
@@ -74,14 +74,13 @@ class BlockRenderOrderTest extends WebTestBase {
 
     $controller = $this->container->get('entity.manager')->getStorageController('block');
     foreach ($controller->loadMultiple() as $return_block) {
-      $settings = $return_block->get('settings');
       $id = $return_block->get('id');
       if ($return_block_weight = $return_block->get('weight')) {
         $this->assertTrue($test_blocks[$id]['weight'] == $return_block_weight, 'Block weight is set as "' . $return_block_weight  . '" for ' . $id . ' block.');
-        $position[$id] = strpos($test_content, 'block-' . $test_blocks[$id]['machine_name']);
+        $position[$id] = strpos($test_content, drupal_html_class('block-' . $test_blocks[$id]['id']));
       }
     }
-    $this->assertTrue($position['stark.powered'] < $position['stark.by'], 'Blocks with different weight are rendered in the correct order.');
-    $this->assertTrue($position['stark.drupal'] < $position['stark.by'], 'Blocks with identical weight are rendered in reverse alphabetical order.');
+    $this->assertTrue($position['stark_powered'] < $position['stark_by'], 'Blocks with different weight are rendered in the correct order.');
+    $this->assertTrue($position['stark_drupal'] < $position['stark_by'], 'Blocks with identical weight are rendered in reverse alphabetical order.');
   }
 }
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php
index d79d8435ca1..82827abd8b1 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockStorageUnitTest.php
@@ -76,7 +76,8 @@ class BlockStorageUnitTest extends DrupalUnitTestBase {
 
     // Create a block with only required values.
     $entity = $this->controller->create(array(
-      'id' => 'stark.test_block',
+      'id' => 'test_block',
+      'theme' => 'stark',
       'plugin' => 'test_html_id',
     ));
     $entity->save();
@@ -84,16 +85,17 @@ class BlockStorageUnitTest extends DrupalUnitTestBase {
     $this->assertTrue($entity instanceof Block, 'The newly created entity is a Block.');
 
     // Verify all of the block properties.
-    $actual_properties = \Drupal::config('block.block.stark.test_block')->get();
+    $actual_properties = \Drupal::config('block.block.test_block')->get();
     $this->assertTrue(!empty($actual_properties['uuid']), 'The block UUID is set.');
     unset($actual_properties['uuid']);
 
     // Ensure that default values are filled in.
     $expected_properties = array(
-      'id' => 'stark.test_block',
+      'id' => 'test_block',
       'weight' => NULL,
       'status' => TRUE,
       'langcode' => language_default()->id,
+      'theme' => 'stark',
       'region' => -1,
       'plugin' => 'test_html_id',
       'settings' => array(
@@ -113,7 +115,7 @@ class BlockStorageUnitTest extends DrupalUnitTestBase {
    * Tests the rendering of blocks.
    */
   protected function loadTests() {
-    $entity = $this->controller->load('stark.test_block');
+    $entity = $this->controller->load('test_block');
 
     $this->assertTrue($entity instanceof Block, 'The loaded entity is a Block.');
 
@@ -129,7 +131,7 @@ class BlockStorageUnitTest extends DrupalUnitTestBase {
    */
   protected function renderTests() {
     // Test the rendering of a block.
-    $entity = entity_load('block', 'stark.test_block');
+    $entity = entity_load('block', 'test_block');
     $output = entity_view($entity, 'block');
     $expected = array();
     $expected[] = '<div class="block block-block-test" id="block-test-block">';
@@ -149,7 +151,8 @@ class BlockStorageUnitTest extends DrupalUnitTestBase {
 
     // Test the rendering of a block with a given title.
     $entity = $this->controller->create(array(
-      'id' => 'stark.test_block2',
+      'id' => 'test_block2',
+      'theme' => 'stark',
       'plugin' => 'test_html_id',
       'settings' => array(
         'label' => 'Powered by Bananas',
@@ -178,7 +181,7 @@ class BlockStorageUnitTest extends DrupalUnitTestBase {
    * Tests the deleting of blocks.
    */
   protected function deleteTests() {
-    $entity = $this->controller->load('stark.test_block');
+    $entity = $this->controller->load('test_block');
 
     // Ensure that the storage isn't currently empty.
     $config_storage = $this->container->get('config.storage');
@@ -205,7 +208,7 @@ class BlockStorageUnitTest extends DrupalUnitTestBase {
 
     $entities = $this->controller->loadMultiple();
     $entity = reset($entities);
-    $this->assertEqual($entity->id(), 'stark.test_block', 'The default test block was loaded.');
+    $this->assertEqual($entity->id(), 'test_block', 'The default test block was loaded.');
   }
 
 }
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
index 8289eb4ed1d..6d962edfbf9 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockTemplateSuggestionsUnitTest.php
@@ -40,7 +40,7 @@ class BlockTemplateSuggestionsUnitTest extends WebTestBase {
     $block = entity_create('block', array(
       'plugin' => 'system_menu_block:admin',
       'region' => 'footer',
-      'id' => \Drupal::config('system.theme')->get('default') . '.machinename',
+      'id' => 'machinename',
     ));
 
     $variables = array();
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockTest.php
index fe1dca18eb1..27bf1b28d30 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockTest.php
@@ -32,7 +32,7 @@ class BlockTest extends BlockTestBase {
     // Enable a standard block.
     $default_theme = \Drupal::config('system.theme')->get('default');
     $edit = array(
-      'machine_name' => strtolower($this->randomName(8)),
+      'id' => strtolower($this->randomName(8)),
       'region' => 'sidebar_first',
       'settings[label]' => $title,
     );
@@ -73,7 +73,7 @@ class BlockTest extends BlockTestBase {
     // Enable a standard block.
     $default_theme = \Drupal::config('system.theme')->get('default');
     $edit = array(
-      'machine_name' => strtolower($this->randomName(8)),
+      'id' => strtolower($this->randomName(8)),
       'region' => 'sidebar_first',
       'settings[label]' => $title,
       'visibility[path][visibility]' => BLOCK_VISIBILITY_LISTED,
@@ -103,15 +103,14 @@ class BlockTest extends BlockTestBase {
     $block = array();
     $block['id'] = 'system_powered_by_block';
     $block['settings[label]'] = $this->randomName(8);
-    $block['machine_name'] = strtolower($this->randomName(8));
     $block['theme'] = \Drupal::config('system.theme')->get('default');
     $block['region'] = 'header';
 
     // Set block title to confirm that interface works and override any custom titles.
-    $this->drupalPostForm('admin/structure/block/add/' . $block['id'] . '/' . $block['theme'], array('settings[label]' => $block['settings[label]'], 'machine_name' => $block['machine_name'], 'region' => $block['region']), t('Save block'));
+    $this->drupalPostForm('admin/structure/block/add/' . $block['id'] . '/' . $block['theme'], array('settings[label]' => $block['settings[label]'], 'id' => $block['id'], 'region' => $block['region']), t('Save block'));
     $this->assertText(t('The block configuration has been saved.'), 'Block title set.');
     // Check to see if the block was created by checking its configuration.
-    $instance = entity_load('block', $block['theme'] . '.' . $block['machine_name']);
+    $instance = entity_load('block', $block['id']);
 
     $this->assertEqual($instance->label(), $block['settings[label]'], 'Stored block title found.');
 
@@ -122,7 +121,7 @@ class BlockTest extends BlockTestBase {
 
     // Set the block to the disabled region.
     $edit = array();
-    $edit['blocks[' . $block['theme'] . '.' . $block['machine_name'] . '][region]'] = -1;
+    $edit['blocks[' . $block['id'] . '][region]'] = -1;
     $this->drupalPostForm('admin/structure/block', $edit, t('Save blocks'));
 
     // Confirm that the block is now listed as disabled.
@@ -133,11 +132,11 @@ class BlockTest extends BlockTestBase {
     $this->assertNoText(t($block['settings[label]']));
     // Check for <div id="block-my-block-instance-name"> if the machine name
     // is my_block_instance_name.
-    $xpath = $this->buildXPathQuery('//div[@id=:id]/*', array(':id' => 'block-' . strtr(strtolower($block['machine_name']), '-', '_')));
+    $xpath = $this->buildXPathQuery('//div[@id=:id]/*', array(':id' => 'block-' . str_replace('_', '-', strtolower($block['id']))));
     $this->assertNoFieldByXPath($xpath, FALSE, 'Block found in no regions.');
 
     // Test deleting the block from the edit form.
-    $this->drupalGet('admin/structure/block/manage/' . $block['theme'] . '.' . $block['machine_name']);
+    $this->drupalGet('admin/structure/block/manage/' . $block['id']);
     $this->drupalPostForm(NULL, array(), t('Delete'));
     $this->assertRaw(t('Are you sure you want to delete the block %name?', array('%name' => $block['settings[label]'])));
     $this->drupalPostForm(NULL, array(), t('Delete'));
@@ -154,17 +153,17 @@ class BlockTest extends BlockTestBase {
     foreach (array('bartik', 'stark', 'seven') as $theme) {
       // Select the 'Powered by Drupal' block to be placed.
       $block = array();
-      $block['machine_name'] = strtolower($this->randomName(8));
+      $block['id'] = strtolower($this->randomName());
       $block['theme'] = $theme;
       $block['region'] = 'content';
       $this->drupalPostForm('admin/structure/block/add/system_powered_by_block', $block, t('Save block'));
       $this->assertText(t('The block configuration has been saved.'));
-      $this->assertUrl('admin/structure/block/list/' . $theme . '?block-placement=' . drupal_html_class($theme . ':' . $block['machine_name']));
+      $this->assertUrl('admin/structure/block/list/' . $theme . '?block-placement=' . drupal_html_class($block['id']));
 
       // Set the default theme and ensure the block is placed.
       $theme_settings->set('default', $theme)->save();
       $this->drupalGet('');
-      $elements = $this->xpath('//div[@id = :id]', array(':id' => drupal_html_id('block-' . $block['machine_name'])));
+      $elements = $this->xpath('//div[@id = :id]', array(':id' => drupal_html_id('block-' . $block['id'])));
       $this->assertTrue(!empty($elements), 'The block was found.');
     }
   }
@@ -176,11 +175,11 @@ class BlockTest extends BlockTestBase {
     $block_name = 'system_powered_by_block';
     // Create a random title for the block.
     $title = $this->randomName(8);
-    $machine_name = strtolower($this->randomName(8));
+    $id = strtolower($this->randomName(8));
     // Enable a standard block.
     $default_theme = \Drupal::config('system.theme')->get('default') ?: 'stark';
     $edit = array(
-      'machine_name' => $machine_name,
+      'id' => $id,
       'region' => 'sidebar_first',
       'settings[label]' => $title,
     );
@@ -193,7 +192,7 @@ class BlockTest extends BlockTestBase {
     $edit = array(
       'settings[label_display]' => FALSE,
     );
-    $this->drupalPostForm('admin/structure/block/manage/' . $default_theme . '.' . $machine_name, $edit, t('Save block'));
+    $this->drupalPostForm('admin/structure/block/manage/' . $id, $edit, t('Save block'));
     $this->assertText('The block configuration has been saved.', 'Block was saved');
 
     $this->drupalGet('user');
@@ -216,7 +215,7 @@ class BlockTest extends BlockTestBase {
     // Set the created block to a specific region.
     $block += array('theme' => \Drupal::config('system.theme')->get('default'));
     $edit = array();
-    $edit['blocks[' . $block['theme'] . '.' . $block['machine_name'] . '][region]'] = $region;
+    $edit['blocks[' . $block['id'] . '][region]'] = $region;
     $this->drupalPostForm('admin/structure/block', $edit, t('Save blocks'));
 
     // Confirm that the block was moved to the proper region.
@@ -229,7 +228,7 @@ class BlockTest extends BlockTestBase {
     // Confirm that the custom block was found at the proper region.
     $xpath = $this->buildXPathQuery('//div[@class=:region-class]//div[@id=:block-id]/*', array(
       ':region-class' => 'region region-' . drupal_html_class($region),
-      ':block-id' => 'block-' . strtr(strtolower($block['machine_name']), '-', '_'),
+      ':block-id' => 'block-' . str_replace('_', '-', strtolower($block['id'])),
     ));
     $this->assertFieldByXPath($xpath, NULL, t('Block found in %region_name region.', array('%region_name' => drupal_html_class($region))));
   }
@@ -247,7 +246,6 @@ class BlockTest extends BlockTestBase {
     // Add a test block.
     $block = array();
     $block['id'] = 'test_cache';
-    $block['machine_name'] = strtolower($this->randomName(8));
     $block['theme'] = \Drupal::config('system.theme')->get('default');
     $block['region'] = 'header';
     $block = $this->drupalPlaceBlock('test_cache', array('region' => 'header'));
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockTestBase.php b/core/modules/block/lib/Drupal/block/Tests/BlockTestBase.php
index 117e7c140d2..3dbbf90eca0 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockTestBase.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockTestBase.php
@@ -66,40 +66,10 @@ abstract class BlockTestBase extends WebTestBase {
       'sidebar_second',
       'footer',
     );
-
+    $block_storage = $this->container->get('entity.manager')->getStorageController('block');
+    $blocks = $block_storage->loadByProperties(array('theme' => \Drupal::config('system.theme')->get('default')));
+    foreach ($blocks as $block) {
+      $block->delete();
+    }
   }
-
-  /**
-   * Moves a block to a given region via the UI and confirms the result.
-   *
-   * @param array $block
-   *   An array of information about the block, including the following keys:
-   *   - module: The module providing the block.
-   *   - title: The title of the block.
-   *   - delta: The block's delta key.
-   * @param string $region
-   *   The machine name of the theme region to move the block to, for example
-   *   'header' or 'sidebar_first'.
-   */
-  function moveBlockToRegion(array $block, $region) {
-    // Set the created block to a specific region.
-    $edit = array();
-    $edit['blocks[0][region]'] = $region;
-    $this->drupalPostForm('admin/structure/block', $edit, t('Save blocks'));
-
-    // Confirm that the block was moved to the proper region.
-    $this->assertText(t('The block settings have been updated.'), format_string('Block successfully moved to %region_name region.', array( '%region_name' => $region)));
-
-    // Confirm that the block is being displayed.
-    $this->drupalGet('');
-    $this->assertText(t($block['title']), 'Block successfully being displayed on the page.');
-
-    // Confirm that the custom block was found at the proper region.
-    $xpath = $this->buildXPathQuery('//div[@class=:region-class]//div[@id=:block-id]/*', array(
-     ':region-class' => 'region region-' . drupal_html_class($region),
-     ':block-id' => 'block-' . strtr(strtolower($block['machine_name']), '-', '_'),
-    ));
-    $this->assertFieldByXPath($xpath, NULL, t('Block found in %region_name region.', array('%region_name' => drupal_html_class($region))));
-  }
-
 }
diff --git a/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php b/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php
index da7648478d5..05921ed2f68 100644
--- a/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/BlockUiTest.php
@@ -51,14 +51,14 @@ class BlockUiTest extends WebTestBase {
         'label' => 'Tools',
         'tr' => '5',
         'plugin_id' => 'system_menu_block:tools',
-        'settings' => array('region' => 'sidebar_second', 'machine_name' => 'tools'),
+        'settings' => array('region' => 'sidebar_second', 'id' => 'tools'),
         'test_weight' => '-1',
       ),
       array(
         'label' => 'Powered by Drupal',
         'tr' => '12',
         'plugin_id' => 'system_powered_by_block',
-        'settings' => array('region' => 'footer', 'machine_name' => 'powered'),
+        'settings' => array('region' => 'footer', 'id' => 'powered'),
         'test_weight' => '0',
       ),
     );
@@ -92,24 +92,24 @@ class BlockUiTest extends WebTestBase {
       $element = $this->xpath('//*[@id="blocks"]/tbody/tr[' . $values['tr'] . ']/td[1]/text()');
       $this->assertTrue((string)$element[0] == $values['label'], 'The "' . $values['label'] . '" block title is set inside the ' . $values['settings']['region'] . ' region.');
       // Look for a test block region select form element.
-      $this->assertField('blocks[stark.' . $values['settings']['machine_name'] . '][region]', 'The block "' . $values['label'] . '" has a region assignment field.');
+      $this->assertField('blocks[' . $values['settings']['id'] . '][region]', 'The block "' . $values['label'] . '" has a region assignment field.');
       // Move the test block to the header region.
-      $edit['blocks[stark.' . $values['settings']['machine_name'] . '][region]'] = 'header';
+      $edit['blocks[' . $values['settings']['id'] . '][region]'] = 'header';
       // Look for a test block weight select form element.
-      $this->assertField('blocks[stark.' . $values['settings']['machine_name'] . '][weight]', 'The block "' . $values['label'] . '" has a weight assignment field.');
+      $this->assertField('blocks[' . $values['settings']['id'] . '][weight]', 'The block "' . $values['label'] . '" has a weight assignment field.');
       // Change the test block's weight.
-      $edit['blocks[stark.' . $values['settings']['machine_name'] . '][weight]'] = $values['test_weight'];
+      $edit['blocks[' . $values['settings']['id'] . '][weight]'] = $values['test_weight'];
     }
     $this->drupalPostForm('admin/structure/block', $edit, t('Save blocks'));
     foreach ($this->testBlocks as $values) {
       // Check if the region and weight settings changes have persisted.
       $this->assertOptionSelected(
-        'edit-blocks-stark' . $values['settings']['machine_name']  . '-region',
+        'edit-blocks-' . $values['settings']['id']  . '-region',
         'header',
         'The block "' . $values['label'] . '" has the correct region assignment (header).'
       );
       $this->assertOptionSelected(
-        'edit-blocks-stark' . $values['settings']['machine_name']  . '-weight',
+        'edit-blocks-' . $values['settings']['id']  . '-weight',
         $values['test_weight'],
         'The block "' . $values['label'] . '" has the correct weight assignment (' . $values['test_weight'] . ').'
       );
@@ -146,17 +146,17 @@ class BlockUiTest extends WebTestBase {
   public function testMachineNameSuggestion() {
     $url = 'admin/structure/block/add/test_block_instantiation/stark';
     $this->drupalGet($url);
-    $this->assertFieldByName('machine_name', 'displaymessage', 'Block form uses raw machine name suggestion when no instance already exists.');
+    $this->assertFieldByName('id', 'displaymessage', 'Block form uses raw machine name suggestion when no instance already exists.');
     $this->drupalPostForm($url, array(), 'Save block');
 
     // Now, check to make sure the form starts by autoincrementing correctly.
     $this->drupalGet($url);
-    $this->assertFieldByName('machine_name', 'displaymessage_2', 'Block form appends _2 to plugin-suggested machine name when an instance already exists.');
+    $this->assertFieldByName('id', 'displaymessage_2', 'Block form appends _2 to plugin-suggested machine name when an instance already exists.');
     $this->drupalPostForm($url, array(), 'Save block');
 
     // And verify that it continues working beyond just the first two.
     $this->drupalGet($url);
-    $this->assertFieldByName('machine_name', 'displaymessage_3', 'Block form appends _3 to plugin-suggested machine name when two instances already exist.');
+    $this->assertFieldByName('id', 'displaymessage_3', 'Block form appends _3 to plugin-suggested machine name when two instances already exist.');
   }
 
 }
diff --git a/core/modules/block/lib/Drupal/block/Tests/NewDefaultThemeBlocksTest.php b/core/modules/block/lib/Drupal/block/Tests/NewDefaultThemeBlocksTest.php
index 00fccc31bcf..b3bf5b9b754 100644
--- a/core/modules/block/lib/Drupal/block/Tests/NewDefaultThemeBlocksTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/NewDefaultThemeBlocksTest.php
@@ -36,16 +36,21 @@ class NewDefaultThemeBlocksTest extends WebTestBase {
     $default_theme = \Drupal::config('system.theme')->get('default');
 
     // Add several block instances.
-    $this->adminUser = $this->drupalCreateUser(array('administer blocks'));
-    $this->drupalLogin($this->adminUser);
+    $this->drupalLogin($this->drupalCreateUser(array('administer blocks')));
 
     // Add two instances of the user login block.
-    $this->drupalPlaceBlock('user_login_block');
-    $this->drupalPlaceBlock('user_login_block');
+    $this->drupalPlaceBlock('user_login_block', array(
+      'id' => $default_theme . '_' . strtolower($this->randomName(8)),
+    ));
+    $this->drupalPlaceBlock('user_login_block', array(
+      'id' => $default_theme . '_' . strtolower($this->randomName(8)),
+    ));
 
     // Add an instance of a different block.
-    $this->drupalPlaceBlock('system_powered_by_block');
-    $this->drupalLogout($this->adminUser);
+    $this->drupalPlaceBlock('system_powered_by_block', array(
+      'id' => $default_theme . '_' . strtolower($this->randomName(8)),
+    ));
+    $this->drupalLogout();
 
     // Enable a different theme.
     $new_theme = 'bartik';
@@ -56,30 +61,18 @@ class NewDefaultThemeBlocksTest extends WebTestBase {
       ->save();
 
     // Ensure that the new theme has all the blocks as the previous default.
-    // @todo Replace the string manipulation below once the configuration
-    //   system provides a method for extracting an ID in a given namespace.
-    $default_prefix = "block.block.$default_theme";
-    $new_prefix = "block.block.$new_theme";
-    $default_block_names = config_get_storage_names_with_prefix($default_prefix);
-    $new_blocks = array_flip(config_get_storage_names_with_prefix($new_prefix));
+    $default_block_names = $this->container->get('entity.query')->get('block')
+      ->condition('theme', $default_theme)
+      ->execute();
+    $new_blocks = $this->container->get('entity.query')->get('block')
+      ->condition('theme', $new_theme)
+      ->execute();
     $this->assertTrue(count($default_block_names) == count($new_blocks), 'The new default theme has the same number of blocks as the previous theme.');
     foreach ($default_block_names as $default_block_name) {
-      // Make sure the configuration object name is in the expected format.
-      if (strpos($default_block_name, $default_prefix) === 0) {
-        // Remove the matching block from the list of blocks in the new theme.
-        // E.g., if the old theme has block.block.stark.admin,
-        // unset block.block.bartik.admin.
-        $id = substr($default_block_name, (strlen($default_prefix) + 1));
-        unset($new_blocks[$new_prefix . '.' . $id]);
-      }
-      else {
-        $this->fail(format_string(
-          '%block is not an expected block instance name.',
-          array(
-            '%block' => $default_block_name,
-          )
-        ));
-      }
+      // Remove the matching block from the list of blocks in the new theme.
+      // E.g., if the old theme has block.block.stark_admin,
+      // unset block.block.bartik_admin.
+      unset($new_blocks[str_replace($default_theme . '_', $new_theme . '_', $default_block_name)]);
     }
     $this->assertTrue(empty($new_blocks), 'The new theme has exactly the same blocks as the previous default theme.');
   }
diff --git a/core/modules/block/lib/Drupal/block/Tests/Views/DisplayBlockTest.php b/core/modules/block/lib/Drupal/block/Tests/Views/DisplayBlockTest.php
index a2e0a55b302..d759c5712e8 100644
--- a/core/modules/block/lib/Drupal/block/Tests/Views/DisplayBlockTest.php
+++ b/core/modules/block/lib/Drupal/block/Tests/Views/DisplayBlockTest.php
@@ -184,11 +184,11 @@ class DisplayBlockTest extends ViewTestBase {
     $this->assertTrue(empty($elements), 'The label field is not found for Views blocks.');
     // Test that that machine name field is hidden from display and has been
     // saved as expected from the default value.
-    $this->assertNoFieldById('edit-machine-name', 'stark.views_block__test_view_block_1', 'The machine name is hidden on the views block form.');
+    $this->assertNoFieldById('edit-machine-name', 'views_block__test_view_block_1', 'The machine name is hidden on the views block form.');
     // Save the block.
     $this->drupalPostForm(NULL, array(), t('Save block'));
     $storage = $this->container->get('entity.manager')->getStorageController('block');
-    $block = $storage->load('stark.views_block__test_view_block_block_1');
+    $block = $storage->load('views_block__test_view_block_block_1');
     // This will only return a result if our new block has been created with the
     // expected machine name.
     $this->assertTrue(!empty($block), 'The expected block was loaded.');
@@ -196,7 +196,7 @@ class DisplayBlockTest extends ViewTestBase {
     for ($i = 2; $i <= 3; $i++) {
       // Place the same block again and make sure we have a new ID.
       $this->drupalPostForm('admin/structure/block/add/views_block:test_view_block-block_1/' . $default_theme, array(), t('Save block'));
-      $block = $storage->load('stark.views_block__test_view_block_block_1_' . $i);
+      $block = $storage->load('views_block__test_view_block_block_1_' . $i);
       // This will only return a result if our new block has been created with the
       // expected machine name.
       $this->assertTrue(!empty($block), 'The expected block was loaded.');
@@ -209,14 +209,14 @@ class DisplayBlockTest extends ViewTestBase {
 
     $this->drupalPostForm('admin/structure/block/add/views_block:test_view_block-block_1/' . $default_theme, $edit, t('Save block'));
 
-    $block = $storage->load('stark.views_block__test_view_block_block_1_4');
+    $block = $storage->load('views_block__test_view_block_block_1_4');
     $config = $block->getPlugin()->getConfiguration();
     $this->assertEqual(10, $config['items_per_page'], "'Items per page' is properly saved.");
 
     $edit['settings[override][items_per_page]'] = 5;
-    $this->drupalPostForm('admin/structure/block/manage/stark.views_block__test_view_block_block_1_4', $edit, t('Save block'));
+    $this->drupalPostForm('admin/structure/block/manage/views_block__test_view_block_block_1_4', $edit, t('Save block'));
 
-    $block = $storage->load('stark.views_block__test_view_block_block_1_4');
+    $block = $storage->load('views_block__test_view_block_block_1_4');
 
     $config = $block->getPlugin()->getConfiguration();
     $this->assertEqual(5, $config['items_per_page'], "'Items per page' is properly saved.");
diff --git a/core/modules/block/tests/modules/block_test/config/block.block.stark.test_block.yml b/core/modules/block/tests/modules/block_test/config/block.block.stark.test_block.yml
index e8b5ade35db..4b68aca9886 100644
--- a/core/modules/block/tests/modules/block_test/config/block.block.stark.test_block.yml
+++ b/core/modules/block/tests/modules/block_test/config/block.block.stark.test_block.yml
@@ -1,4 +1,5 @@
-id: stark.test_block
+id: test_block
+theme: stark
 weight: ''
 status: '1'
 langcode: en
diff --git a/core/modules/language/lib/Drupal/language/Tests/LanguageSwitchingTest.php b/core/modules/language/lib/Drupal/language/Tests/LanguageSwitchingTest.php
index 3d4e25100b5..4613f431172 100644
--- a/core/modules/language/lib/Drupal/language/Tests/LanguageSwitchingTest.php
+++ b/core/modules/language/lib/Drupal/language/Tests/LanguageSwitchingTest.php
@@ -43,7 +43,7 @@ class LanguageSwitchingTest extends WebTestBase {
    */
   function testLanguageBlock() {
     // Enable the language switching block.
-    $block = $this->drupalPlaceBlock('language_block:' . Language::TYPE_INTERFACE, array('machine_name' => 'test_language_block'));
+    $block = $this->drupalPlaceBlock('language_block:' . Language::TYPE_INTERFACE, array('id' => 'test_language_block'));
 
     // Add language.
     $edit = array(
diff --git a/core/modules/language/lib/Drupal/language/Tests/LanguageUILanguageNegotiationTest.php b/core/modules/language/lib/Drupal/language/Tests/LanguageUILanguageNegotiationTest.php
index e87a55014e5..9bee36b3142 100644
--- a/core/modules/language/lib/Drupal/language/Tests/LanguageUILanguageNegotiationTest.php
+++ b/core/modules/language/lib/Drupal/language/Tests/LanguageUILanguageNegotiationTest.php
@@ -408,7 +408,7 @@ class LanguageUILanguageNegotiationTest extends WebTestBase {
     $this->drupalGet('admin/config/regional/language/detection');
 
     // Enable the language switcher block.
-    $this->drupalPlaceBlock('language_block:' . Language::TYPE_INTERFACE, array('machine_name' => 'test_language_block'));
+    $this->drupalPlaceBlock('language_block:' . Language::TYPE_INTERFACE, array('id' => 'test_language_block'));
 
     // Access the front page without specifying any valid URL language prefix
     // and having as browser language preference a non-default language.
diff --git a/core/modules/node/lib/Drupal/node/Tests/NodeBlockFunctionalTest.php b/core/modules/node/lib/Drupal/node/Tests/NodeBlockFunctionalTest.php
index a63bcf8e2c6..70598eec607 100644
--- a/core/modules/node/lib/Drupal/node/Tests/NodeBlockFunctionalTest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/NodeBlockFunctionalTest.php
@@ -61,7 +61,7 @@ class NodeBlockFunctionalTest extends NodeTestBase {
     ));
 
     // Enable the recent content block with two items.
-    $block = $this->drupalPlaceBlock('node_recent_block', array('machine_name' => 'test_block', 'block_count' => 2));
+    $block = $this->drupalPlaceBlock('node_recent_block', array('id' => 'test_block', 'block_count' => 2));
 
     // Test that block is not visible without nodes.
     $this->drupalGet('');
diff --git a/core/modules/node/lib/Drupal/node/Tests/NodeSyndicateBlockTest.php b/core/modules/node/lib/Drupal/node/Tests/NodeSyndicateBlockTest.php
index 887b7eab51b..06a618f9826 100644
--- a/core/modules/node/lib/Drupal/node/Tests/NodeSyndicateBlockTest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/NodeSyndicateBlockTest.php
@@ -40,7 +40,7 @@ class NodeSyndicateBlockTest extends NodeTestBase {
    */
   public function testSyndicateBlock() {
     // Place the "Syndicate" block and confirm that it is rendered.
-    $this->drupalPlaceBlock('node_syndicate_block', array('machine_name' => 'test_syndicate_block'));
+    $this->drupalPlaceBlock('node_syndicate_block', array('id' => 'test_syndicate_block'));
     $this->drupalGet('');
     $this->assertFieldByXPath('//div[@id="block-test-syndicate-block"]/*', NULL, 'Syndicate block found.');
   }
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
index a307e32af87..3da3e93f36a 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/WebTestBase.php
@@ -353,7 +353,7 @@ abstract class WebTestBase extends TestBase {
    *   @endcode
    *   The following defaults are provided:
    *   - label: Random string.
-   *   - machine_name: Random string.
+   *   - id: Random string.
    *   - region: 'sidebar_first'.
    *   - theme: The default theme.
    *   - visibility: Empty array.
@@ -368,20 +368,18 @@ abstract class WebTestBase extends TestBase {
     $settings += array(
       'plugin' => $plugin_id,
       'region' => 'sidebar_first',
-      'machine_name' => strtolower($this->randomName(8)),
+      'id' => strtolower($this->randomName(8)),
       'theme' => \Drupal::config('system.theme')->get('default'),
       'label' => $this->randomName(8),
       'visibility' => array(),
       'weight' => 0,
     );
-    foreach (array('region', 'machine_name', 'theme', 'plugin', 'visibility', 'weight') as $key) {
+    foreach (array('region', 'id', 'theme', 'plugin', 'visibility', 'weight') as $key) {
       $values[$key] = $settings[$key];
       // Remove extra values that do not belong in the settings array.
       unset($settings[$key]);
     }
     $values['settings'] = $settings;
-    // Build the ID out of the theme and machine_name.
-    $values['id'] = $values['theme'] . '.' . $values['machine_name'];
     $block = entity_create('block', $values);
     $block->save();
     return $block;
diff --git a/core/modules/system/lib/Drupal/system/Tests/Menu/BreadcrumbTest.php b/core/modules/system/lib/Drupal/system/Tests/Menu/BreadcrumbTest.php
index 31bc82b9c0a..4c03fa0f8f8 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Menu/BreadcrumbTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Menu/BreadcrumbTest.php
@@ -43,14 +43,12 @@ class BreadcrumbTest extends MenuTestBase {
 
     // This test puts menu links in the Tools menu and then tests for their
     // presence on the page, so we need to ensure that the Tools block will be
-    // displayed in the default theme and admin theme.
-    $settings = array(
-      'machine_name' => 'system_menu_tools',
+    // displayed in the admin theme.
+    $this->drupalPlaceBlock('system_menu_block:tools', array(
+      'machine' => 'system_menu_tools',
       'region' => 'content',
-    );
-    $this->drupalPlaceBlock('system_menu_block:tools', $settings);
-    $settings['theme'] = \Drupal::config('system.theme')->get('admin');
-    $this->drupalPlaceBlock('system_menu_block:tools', $settings);
+      'theme' => \Drupal::config('system.theme')->get('admin'),
+    ));
   }
 
   /**
@@ -279,7 +277,7 @@ class BreadcrumbTest extends MenuTestBase {
       // ('taxonomy/term/%') should never be translated and appear in any menu
       // other than the breadcrumb trail.
       $elements = $this->xpath('//div[@id=:menu]/descendant::a[@href=:href]', array(
-        ':menu' => 'block-system-menu-tools',
+        ':menu' => 'block-bartik-tools',
         ':href' => url($link['link_path']),
       ));
       $this->assertTrue(count($elements) == 1, "Link to {$link['link_path']} appears only once.");
diff --git a/core/modules/system/lib/Drupal/system/Tests/System/AccessDeniedTest.php b/core/modules/system/lib/Drupal/system/Tests/System/AccessDeniedTest.php
index 915e3e8368b..383ace1db44 100644
--- a/core/modules/system/lib/Drupal/system/Tests/System/AccessDeniedTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/System/AccessDeniedTest.php
@@ -54,7 +54,7 @@ class AccessDeniedTest extends WebTestBase {
     $this->drupalPostForm('admin/config/system/site-information', $edit, t('Save configuration'));
 
     // Enable the user login block.
-    $this->drupalPlaceBlock('user_login_block', array('machine_name' => 'login'));
+    $this->drupalPlaceBlock('user_login_block', array('id' => 'login'));
 
     // Log out and check that the user login block is shown on custom 403 pages.
     $this->drupalLogout();
@@ -82,7 +82,7 @@ class AccessDeniedTest extends WebTestBase {
     $edit = array(
       'region' => -1,
     );
-    $this->drupalPostForm('admin/structure/block/manage/stark.login', $edit, t('Save block'));
+    $this->drupalPostForm('admin/structure/block/manage/login', $edit, t('Save block'));
 
     // Check that we can log in from the 403 page.
     $this->drupalLogout();
diff --git a/core/modules/system/lib/Drupal/system/Tests/Upgrade/BlockUpgradePathTest.php b/core/modules/system/lib/Drupal/system/Tests/Upgrade/BlockUpgradePathTest.php
index 79ff2a9b7b7..e1bb4b1656b 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Upgrade/BlockUpgradePathTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Upgrade/BlockUpgradePathTest.php
@@ -43,7 +43,7 @@ class BlockUpgradePathTest extends UpgradePathTestBase {
     // Confirm that the custom block has been created, and title matches input.
     $settings = array(
       'settings[label]' => $this->randomName(255),
-      'machine_name' => strtolower($this->randomName(8)),
+      'id' => strtolower($this->randomName(8)),
       'region' => 'sidebar_first',
     );
     $this->drupalPostForm('admin/structure/block/add/system_powered_by_block/' . \Drupal::config('system.theme')->get('default'), $settings, t('Save block'));
@@ -52,7 +52,7 @@ class BlockUpgradePathTest extends UpgradePathTestBase {
     // Try to add a block with a title over 255 characters.
     $settings = array(
       'settings[label]' => $this->randomName(256),
-      'machine_name' => strtolower($this->randomName(8)),
+      'id' => strtolower($this->randomName(8)),
       'region' => 'sidebar_first',
     );
     $this->drupalPostForm('admin/structure/block/add/system_powered_by_block/' . \Drupal::config('system.theme')->get('default'), $settings, t('Save block'));
diff --git a/core/modules/views/lib/Drupal/views/Plugin/Block/ViewsBlock.php b/core/modules/views/lib/Drupal/views/Plugin/Block/ViewsBlock.php
index 32f861bf744..3f3fe30e69c 100644
--- a/core/modules/views/lib/Drupal/views/Plugin/Block/ViewsBlock.php
+++ b/core/modules/views/lib/Drupal/views/Plugin/Block/ViewsBlock.php
@@ -9,7 +9,7 @@ namespace Drupal\views\Plugin\Block;
 
 use Drupal\block\Annotation\Block;
 use Drupal\Core\Annotation\Translation;
-use Drupal\Core\Entity\EntityStorageControllerInterface;
+use Drupal\Core\Config\Entity\Query\Query;
 use Drupal\Component\Utility\Xss;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
@@ -84,36 +84,6 @@ class ViewsBlock extends ViewsBlockBase {
     }
   }
 
-  /**
-   * Generates a views block instance ID.
-   *
-   * @param \Drupal\Core\Entity\EntityStorageControllerInterface $manager
-   *   The block storage controller.
-   *
-   * @return string
-   *   The new block instance ID.
-   */
-   public function generateBlockInstanceID(EntityStorageControllerInterface $manager) {
-     $original_id = 'views_block__' . $this->view->storage->id() . '_' . $this->view->current_display;
-
-     // Get an array of block IDs without the theme prefix.
-     $block_ids = array_map(function ($block_id) {
-       $parts = explode('.', $block_id);
-       return end($parts);
-     }, array_keys($manager->loadMultiple()));
-
-     // Iterate through potential IDs until we get a new one. E.g.
-     // 'views_block__MYVIEW_PAGE_1_2'
-     $count = 1;
-     $id = $original_id;
-     while (in_array($id, $block_ids)) {
-       $id = $original_id . '_' . ++$count;
-     }
-
-     return $id;
-   }
-
-
   /**
    * {@inheritdoc}
    */
diff --git a/core/modules/views/lib/Drupal/views/Tests/Plugin/ExposedFormTest.php b/core/modules/views/lib/Drupal/views/Tests/Plugin/ExposedFormTest.php
index 05b70354596..33e0b727d0e 100644
--- a/core/modules/views/lib/Drupal/views/Tests/Plugin/ExposedFormTest.php
+++ b/core/modules/views/lib/Drupal/views/Tests/Plugin/ExposedFormTest.php
@@ -120,11 +120,11 @@ class ExposedFormTest extends ViewTestBase {
     $this->drupalGet('test_exposed_block');
 
     // Test there is an exposed form in a block.
-    $xpath = $this->buildXPathQuery('//div[@id=:id]/div/form/@id', array(':id' => 'block-' . $block->get('machine_name')));
+    $xpath = $this->buildXPathQuery('//div[@id=:id]/div/form/@id', array(':id' => drupal_html_id('block-' . $block->id())));
     $this->assertFieldByXpath($xpath, $this->getExpectedExposedFormId($view), 'Expected form found in views block.');
 
     // Test there is not an exposed form in the view page content area.
-    $xpath = $this->buildXPathQuery('//div[@class="view-content"]/form/@id', array(':id' => 'block-' . $block->get('machine_name')));
+    $xpath = $this->buildXPathQuery('//div[@class="view-content"]/form/@id', array(':id' => drupal_html_id('block-' . $block->id())));
     $this->assertNoFieldByXpath($xpath, $this->getExpectedExposedFormId($view), 'No exposed form found in views content region.');
 
     // Test there is only one views exposed form on the page.
diff --git a/core/modules/views/lib/Drupal/views/Tests/ViewTestBase.php b/core/modules/views/lib/Drupal/views/Tests/ViewTestBase.php
index db703fe93fc..86706b504f3 100644
--- a/core/modules/views/lib/Drupal/views/Tests/ViewTestBase.php
+++ b/core/modules/views/lib/Drupal/views/Tests/ViewTestBase.php
@@ -268,9 +268,7 @@ abstract class ViewTestBase extends WebTestBase {
    *   The result from the xpath query.
    */
   protected function findBlockInstance(Block $block) {
-    $config_id = explode('.', $block->id());
-    $machine_name = array_pop($config_id);
-    return $this->xpath('//div[@id = :id]', array(':id' => 'block-' . $machine_name));
+    return $this->xpath('//div[@id = :id]', array(':id' => 'block-' . $block->id()));
   }
 
   /**
diff --git a/core/profiles/minimal/config/block.block.stark.admin.yml b/core/profiles/minimal/config/block.block.stark.admin.yml
index e22ff725c16..1c11ab59058 100644
--- a/core/profiles/minimal/config/block.block.stark.admin.yml
+++ b/core/profiles/minimal/config/block.block.stark.admin.yml
@@ -1,4 +1,5 @@
-id: stark.admin
+id: stark_admin
+theme: stark
 weight: '1'
 status: '1'
 langcode: en
diff --git a/core/profiles/minimal/config/block.block.stark.login.yml b/core/profiles/minimal/config/block.block.stark.login.yml
index b15e39593c9..a727ff5ef00 100644
--- a/core/profiles/minimal/config/block.block.stark.login.yml
+++ b/core/profiles/minimal/config/block.block.stark.login.yml
@@ -1,4 +1,5 @@
-id: stark.login
+id: stark_login
+theme: stark
 weight: '0'
 status: '1'
 langcode: en
diff --git a/core/profiles/minimal/config/block.block.stark.tools.yml b/core/profiles/minimal/config/block.block.stark.tools.yml
index c53d934abab..6073ede0aa2 100644
--- a/core/profiles/minimal/config/block.block.stark.tools.yml
+++ b/core/profiles/minimal/config/block.block.stark.tools.yml
@@ -1,4 +1,5 @@
-id: stark.tools
+id: stark_tools
+theme: stark
 weight: '0'
 status: '1'
 langcode: en
diff --git a/core/profiles/standard/config/block.block.bartik.breadcrumbs.yml b/core/profiles/standard/config/block.block.bartik.breadcrumbs.yml
index b2d19c45686..c915c4690e5 100644
--- a/core/profiles/standard/config/block.block.bartik.breadcrumbs.yml
+++ b/core/profiles/standard/config/block.block.bartik.breadcrumbs.yml
@@ -1,4 +1,5 @@
-id: bartik.breadcrumbs
+id: bartik_breadcrumbs
+theme: bartik
 uuid: a29e843f-d19c-4528-ab02-2fc335e12b1e
 weight: '-5'
 status: '0'
diff --git a/core/profiles/standard/config/block.block.bartik.content.yml b/core/profiles/standard/config/block.block.bartik.content.yml
index ae0fe804c6e..5b7187b0733 100644
--- a/core/profiles/standard/config/block.block.bartik.content.yml
+++ b/core/profiles/standard/config/block.block.bartik.content.yml
@@ -1,4 +1,5 @@
-id: bartik.content
+id: bartik_content
+theme: bartik
 uuid: 2cab5a0c-de08-4b5c-9700-f0243a6fb000
 weight: '0'
 status: '1'
diff --git a/core/profiles/standard/config/block.block.bartik.footer.yml b/core/profiles/standard/config/block.block.bartik.footer.yml
index 8519cab3119..2ad2766bb54 100644
--- a/core/profiles/standard/config/block.block.bartik.footer.yml
+++ b/core/profiles/standard/config/block.block.bartik.footer.yml
@@ -1,4 +1,5 @@
-id: bartik.footer
+id: bartik_footer
+theme: bartik
 uuid: a6c75fc2-5ca1-403e-ab37-557c7244e8c0
 weight: '0'
 status: '1'
diff --git a/core/profiles/standard/config/block.block.bartik.help.yml b/core/profiles/standard/config/block.block.bartik.help.yml
index 00c1176993e..c697560d648 100644
--- a/core/profiles/standard/config/block.block.bartik.help.yml
+++ b/core/profiles/standard/config/block.block.bartik.help.yml
@@ -1,4 +1,5 @@
-id: bartik.help
+id: bartik_help
+theme: bartik
 uuid: 6ea8e05a-6793-4ecf-8801-015dc6e1013e
 weight: '0'
 status: '1'
diff --git a/core/profiles/standard/config/block.block.bartik.login.yml b/core/profiles/standard/config/block.block.bartik.login.yml
index 9a82618b338..e94f5623e6a 100644
--- a/core/profiles/standard/config/block.block.bartik.login.yml
+++ b/core/profiles/standard/config/block.block.bartik.login.yml
@@ -1,4 +1,5 @@
-id: bartik.login
+id: bartik_login
+theme: bartik
 uuid: 961f4152-3e91-4c9f-9114-20a5375675d0
 weight: '0'
 status: '1'
diff --git a/core/profiles/standard/config/block.block.bartik.powered.yml b/core/profiles/standard/config/block.block.bartik.powered.yml
index 1dbe2db0cad..265f2716c33 100644
--- a/core/profiles/standard/config/block.block.bartik.powered.yml
+++ b/core/profiles/standard/config/block.block.bartik.powered.yml
@@ -1,4 +1,5 @@
-id: bartik.powered
+id: bartik_powered
+theme: bartik
 uuid: 37cff101-27dc-478d-9d00-b58b9d884039
 weight: '10'
 status: '1'
diff --git a/core/profiles/standard/config/block.block.bartik.search.yml b/core/profiles/standard/config/block.block.bartik.search.yml
index 8d1f94bcd8f..d37e197281a 100644
--- a/core/profiles/standard/config/block.block.bartik.search.yml
+++ b/core/profiles/standard/config/block.block.bartik.search.yml
@@ -1,4 +1,5 @@
-id: bartik.search
+id: bartik_search
+theme: bartik
 uuid: 51f70058-a370-4410-9000-a65488d00e6c
 weight: '-1'
 status: '1'
diff --git a/core/profiles/standard/config/block.block.bartik.tools.yml b/core/profiles/standard/config/block.block.bartik.tools.yml
index 0a9e6fafbaa..b94065195e9 100644
--- a/core/profiles/standard/config/block.block.bartik.tools.yml
+++ b/core/profiles/standard/config/block.block.bartik.tools.yml
@@ -1,4 +1,5 @@
-id: bartik.tools
+id: bartik_tools
+theme: bartik
 uuid: 0dca3209-c6fa-4043-a407-7afb952cfc5e
 weight: '0'
 status: '1'
diff --git a/core/profiles/standard/config/block.block.seven.breadcrumbs.yml b/core/profiles/standard/config/block.block.seven.breadcrumbs.yml
index cbe50e64bc8..d31403117bc 100644
--- a/core/profiles/standard/config/block.block.seven.breadcrumbs.yml
+++ b/core/profiles/standard/config/block.block.seven.breadcrumbs.yml
@@ -1,4 +1,5 @@
-id: seven.breadcrumbs
+id: seven_breadcrumbs
+theme: seven
 uuid: f8d0d0fb-daf7-4c91-8a09-9cb643279f03
 weight: '-2'
 status: '0'
diff --git a/core/profiles/standard/config/block.block.seven.content.yml b/core/profiles/standard/config/block.block.seven.content.yml
index 6e64d8935ed..39f26ffcd2b 100644
--- a/core/profiles/standard/config/block.block.seven.content.yml
+++ b/core/profiles/standard/config/block.block.seven.content.yml
@@ -1,4 +1,5 @@
-id: seven.content
+id: seven_content
+theme: seven
 uuid: 3c9e3337-e0f4-42c3-8a00-f1d8be09b0ea
 weight: '0'
 status: '1'
diff --git a/core/profiles/standard/config/block.block.seven.help.yml b/core/profiles/standard/config/block.block.seven.help.yml
index ebfdfe7f641..8536232d6d0 100644
--- a/core/profiles/standard/config/block.block.seven.help.yml
+++ b/core/profiles/standard/config/block.block.seven.help.yml
@@ -1,4 +1,5 @@
-id: seven.help
+id: seven_help
+theme: seven
 uuid: 367d09b7-9638-4faf-bf07-7fe31b2226a0
 weight: '0'
 status: '1'
diff --git a/core/profiles/standard/config/block.block.seven.login.yml b/core/profiles/standard/config/block.block.seven.login.yml
index 61c70b1dd55..d3e62fa0cf2 100644
--- a/core/profiles/standard/config/block.block.seven.login.yml
+++ b/core/profiles/standard/config/block.block.seven.login.yml
@@ -1,4 +1,5 @@
-id: seven.login
+id: seven_login
+theme: seven
 uuid: 10a9888b-2247-408d-9702-2c0cc9cacba2
 weight: '10'
 status: '1'
diff --git a/core/profiles/standard/lib/Drupal/standard/Tests/StandardTest.php b/core/profiles/standard/lib/Drupal/standard/Tests/StandardTest.php
index 31fa0fe36c1..9857b8362b8 100644
--- a/core/profiles/standard/lib/Drupal/standard/Tests/StandardTest.php
+++ b/core/profiles/standard/lib/Drupal/standard/Tests/StandardTest.php
@@ -40,7 +40,7 @@ class StandardTest extends WebTestBase {
     $this->drupalGet('admin/structure/block/add/system_menu_block:main/bartik');
     $this->drupalPostForm(NULL, array(
       'region' => 'sidebar_first',
-      'machine_name' => 'main_navigation',
+      'id' => 'main_navigation',
     ), t('Save block'));
     // Verify admin user can see the block.
     $this->drupalGet('');
@@ -51,7 +51,7 @@ class StandardTest extends WebTestBase {
     $this->drupalGet('admin/structure/block');
     $elements = $this->xpath('//div[@role=:role and @id=:id]', array(
       ':role' => 'complementary',
-      ':id' => 'block-help',
+      ':id' => 'block-bartik-help',
     ));
 
     $this->assertEqual(count($elements), 1, 'Found complementary role on help block.');
@@ -59,7 +59,7 @@ class StandardTest extends WebTestBase {
     $this->drupalGet('');
     $elements = $this->xpath('//div[@role=:role and @id=:id]', array(
       ':role' => 'complementary',
-      ':id' => 'block-powered',
+      ':id' => 'block-bartik-powered',
     ));
     $this->assertEqual(count($elements), 1, 'Found complementary role on powered by block.');