diff --git a/web/pgadmin/static/js/helpers/ModalProvider.jsx b/web/pgadmin/static/js/helpers/ModalProvider.jsx
index 850f537f6..b7b9ee867 100644
--- a/web/pgadmin/static/js/helpers/ModalProvider.jsx
+++ b/web/pgadmin/static/js/helpers/ModalProvider.jsx
@@ -131,8 +131,8 @@ export default function ModalProvider({ children }) {
   return (
     <ModalContext.Provider value={modalContext}>
       {children}
-      {modals.map((modalOptions, i) => (
-        <ModalContainer key={i} {...modalOptions} />
+      {modals.map((modalOptions) => (
+        <ModalContainer key={modalOptions.id} {...modalOptions} />
       ))}
     </ModalContext.Provider>
   );
diff --git a/web/pgadmin/tools/user_management/__init__.py b/web/pgadmin/tools/user_management/__init__.py
index e07c27433..4a310e323 100644
--- a/web/pgadmin/tools/user_management/__init__.py
+++ b/web/pgadmin/tools/user_management/__init__.py
@@ -400,6 +400,12 @@ def save():
     )
 
     try:
+        # Delete Users
+        if 'deleted' in data:
+            for item in data['deleted']:
+                status, res = delete_user(item['id'])
+                if not status:
+                    return internal_server_error(errormsg=res)
         # Create Users
         if 'added' in data:
             for item in data['added']:
@@ -412,13 +418,6 @@ def save():
                 status, res = update_user(item['id'], item)
                 if not status:
                     return internal_server_error(errormsg=res)
-
-        # Delete Users
-        if 'deleted' in data:
-            for item in data['deleted']:
-                status, res = delete_user(item['id'])
-                if not status:
-                    return internal_server_error(errormsg=res)
     except Exception as e:
         return internal_server_error(errormsg=str(e))
 
diff --git a/web/pgadmin/tools/user_management/static/js/UserManagementDialog.jsx b/web/pgadmin/tools/user_management/static/js/UserManagementDialog.jsx
index b07559eb4..51b2b5c3a 100644
--- a/web/pgadmin/tools/user_management/static/js/UserManagementDialog.jsx
+++ b/web/pgadmin/tools/user_management/static/js/UserManagementDialog.jsx
@@ -149,6 +149,20 @@ class UserManagementCollection extends BaseUISchema {
       setError('username', null);
     }
 
+    if (state.auth_source != authConstant['INTERNAL']) {
+      if (obj.isNew(state) && obj.top?._sessData?.userManagement) {
+        for (let i=0; i < obj.top._sessData.userManagement.length; i++) {
+          if (obj.top._sessData.userManagement[i]?.id &&
+            obj.top._sessData.userManagement[i].username == state.username &&
+            obj.top._sessData.userManagement[i].auth_source == state.auth_source) {
+            msg = gettext('User name \'%s\' already exists', state.username);
+            setError('username', msg);
+            return true;
+          }
+        }
+      }
+    }
+
     if (state.auth_source == authConstant['INTERNAL']) {
       let email_filter = /^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$/;
       if (isEmptyString(state.email)) {