diff --git a/core/lib/Drupal/Core/Block/BlockBase.php b/core/lib/Drupal/Core/Block/BlockBase.php
index fc614b0121c..bcc3954ae69 100644
--- a/core/lib/Drupal/Core/Block/BlockBase.php
+++ b/core/lib/Drupal/Core/Block/BlockBase.php
@@ -245,7 +245,7 @@ abstract class BlockBase extends ContextAwarePluginBase implements BlockPluginIn
     $transliterated = $this->transliteration()->transliterate($admin_label, LanguageInterface::LANGCODE_DEFAULT, '_');
     $transliterated = Unicode::strtolower($transliterated);
 
-    $transliterated = preg_replace('@[^a-z0-9_]+@', '', $transliterated);
+    $transliterated = preg_replace('@[^a-z0-9_.]+@', '', $transliterated);
 
     return $transliterated;
   }
diff --git a/core/modules/block/src/BlockForm.php b/core/modules/block/src/BlockForm.php
index 8417c3597fd..35258b8cd94 100644
--- a/core/modules/block/src/BlockForm.php
+++ b/core/modules/block/src/BlockForm.php
@@ -147,7 +147,7 @@ class BlockForm extends EntityForm {
       '#default_value' => !$entity->isNew() ? $entity->id() : $this->getUniqueMachineName($entity),
       '#machine_name' => array(
         'exists' => '\Drupal\block\Entity\Block::load',
-        'replace_pattern' => '[^a-z0-9_]+',
+        'replace_pattern' => '[^a-z0-9_.]+',
         'source' => array('settings', 'label'),
       ),
       '#required' => TRUE,
diff --git a/core/modules/block/tests/src/Kernel/BlockMachineNameTest.php b/core/modules/block/tests/src/Kernel/BlockMachineNameTest.php
deleted file mode 100644
index 34c2635fdf0..00000000000
--- a/core/modules/block/tests/src/Kernel/BlockMachineNameTest.php
+++ /dev/null
@@ -1,86 +0,0 @@
-<?php
-
-namespace Drupal\Tests\block\Kernel;
-
-
-use Drupal\block_content\Entity\BlockContent;
-use Drupal\block_content\Entity\BlockContentType;
-use Drupal\Component\Plugin\PluginBase;
-use Drupal\KernelTests\KernelTestBase;
-use Drupal\simpletest\BlockCreationTrait;
-
-/**
- * Tests block machine names.
- *
- * @group block
- */
-class BlockMachineNameTest extends KernelTestBase {
-
-  use BlockCreationTrait;
-  /**
-   * {@inheritdoc}
-   */
-  public static $modules = ['block', 'block_content', 'system', 'user'];
-
-  /**
-   * {@inheritdoc}
-   */
-  public function setUp() {
-    parent::setUp();
-    $this->installSchema('system', ['sequence']);
-    $this->installEntitySchema('block_content');
-    $this->installEntitySchema('user');
-  }
-
-  /**
-   * Tests machine name collisions.
-   */
-  public function testMachineNamesShouldNotCollideIfBlockTitlesContainPeriod() {
-    // Create a block type.
-    $type = BlockContentType::create([
-      'id' => 'whizzy',
-      'label' => 'Tis whizzy',
-    ]);
-    $type->save();
-
-    // And a block content entity.
-    $block_content = BlockContent::create([
-      'type' => 'Tis whizzy',
-      'info' => 'This. is whizzy',
-    ]);
-    $block_content->save();
-
-    // Use \Drupal\Core\Block\BlockBase::getMachineNameSuggestion to generate
-    // an ID.
-    $plugin_id = 'block_content' . PluginBase::DERIVATIVE_SEPARATOR . $block_content->uuid();
-    $block_plugin = $this->container->get('plugin.manager.block')->createInstance($plugin_id, []);
-    $method = new \ReflectionMethod($block_plugin, 'getMachineNameSuggestion');
-    $method->setAccessible(TRUE);
-    $id = $method->invoke($block_plugin);
-
-    // Now place the block content entity.
-    $block = $this->placeBlock($plugin_id, [
-      'label' => 'This. is whizzy',
-      'id' => $id,
-    ]);
-
-    $theme = $this->container->get('config.factory')->get('system.theme')->get('default');
-
-    // Create a new entity.
-    /** @var \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager */
-    $entity_type_manager = $this->container->get('entity_type.manager');
-    $new_entity = $entity_type_manager->getStorage('block')->create(array('plugin' => $plugin_id, 'theme' => $theme));
-
-    // Now generate a default ID like
-    // \Drupal\block\BlockForm::getUniqueMachineName does.
-    /** @var \Drupal\block\BlockForm $form_object */
-    $form_object = $entity_type_manager->getFormObject('block', 'default');
-    $form_object->setEntity($new_entity);
-
-    $unique_id = $form_object->getUniqueMachineName($new_entity);
-
-    // Assert that the new ID is different to the old one.
-    $this->assertNotEquals($unique_id, $block->id());
-  }
-
-}