diff --git a/core/modules/comment/comment.tokens.inc b/core/modules/comment/comment.tokens.inc
index 715b63d..f5afcab 100644
--- a/core/modules/comment/comment.tokens.inc
+++ b/core/modules/comment/comment.tokens.inc
@@ -216,7 +216,7 @@ function comment_tokens($type, $tokens, array $data = array(), array $options =
     }
 
     if (($author_tokens = token_find_with_prefix($tokens, 'author')) && $account = $comment->uid->entity) {
-      $replacements += token_generate('user', $author_tokens, array('user' => $account), $options);
+      $replacements += token_generate('user', $author_tokens, array('user' => $account->getBCEntity()), $options);
     }
   }
   elseif ($type == 'node' & !empty($data['node'])) {
diff --git a/core/modules/comment/lib/Drupal/comment/Tests/CommentLinksTest.php b/core/modules/comment/lib/Drupal/comment/Tests/CommentLinksTest.php
index 7907464..1388d13 100644
--- a/core/modules/comment/lib/Drupal/comment/Tests/CommentLinksTest.php
+++ b/core/modules/comment/lib/Drupal/comment/Tests/CommentLinksTest.php
@@ -50,7 +50,8 @@ function testCommentLinks() {
 
     // Remove additional user permissions from $this->web_user added by setUp(),
     // since this test is limited to anonymous and authenticated roles only.
-    entity_delete_multiple('user_role', array(key($this->web_user->roles)));
+    $roles = $this->web_user->roles;
+    entity_delete_multiple('user_role', array(reset($roles)));
 
     // Matrix of possible environmental conditions and configuration settings.
     // See setEnvironment() for details.
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php b/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php
index cee642e..eb257dc 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php
@@ -88,7 +88,7 @@ function testConfigLocaleUserOverride() {
     ));
 
     $user_config_context = config_context_enter('Drupal\user\UserConfigContext');
-    $user_config_context->setAccount($account);
+    $user_config_context->setAccount($account->getOriginalEntity());
     $config = config('config_test.system');
     $this->assertIdentical($config->get('foo'), 'fr bar');
     // Ensure the non-overriden value is still the same.
@@ -111,7 +111,7 @@ function testConfigLocaleUserOverride() {
     ));
 
     $config_factory = drupal_container()->get('config.factory');
-    $config_factory->enterContext($user_config_context->setAccount($account));
+    $config_factory->enterContext($user_config_context->setAccount($account->getOriginalEntity()));
     // Should not have to re-initialize the configuration object to get new
     // overrides as the new context will have a different uuid.
     $config = config('config_test.system');
@@ -127,7 +127,7 @@ function testConfigLocaleUserOverride() {
     ));
     // Create a new user config context to stack on top of the existign one.
     $en_user_config_context = config_context_enter('Drupal\user\UserConfigContext');
-    $en_user_config_context->setAccount($account);
+    $en_user_config_context->setAccount($account->getOriginalEntity());
     $config = config('config_test.system');
     $this->assertIdentical($config->get('foo'), 'en bar');
 
@@ -178,7 +178,7 @@ function testConfigLocaleUserAndGlobalOverride() {
     ));
 
     $user_config_context = config_context_enter('Drupal\user\UserConfigContext');
-    $user_config_context->setAccount($account);
+    $user_config_context->setAccount($account->getOriginalEntity());
     $config = config('config_test.system');
     $this->assertIdentical($config->get('foo'), 'fr bar');
     // Ensure the value overriden from global $conf works.
diff --git a/core/modules/contact/lib/Drupal/contact/MessageFormController.php b/core/modules/contact/lib/Drupal/contact/MessageFormController.php
index c4352cf..b3a9ed8 100644
--- a/core/modules/contact/lib/Drupal/contact/MessageFormController.php
+++ b/core/modules/contact/lib/Drupal/contact/MessageFormController.php
@@ -167,7 +167,7 @@ public function save(array $form, array &$form_state) {
       $to = implode(', ', $category->recipients);
       $recipient_langcode = language_default()->langcode;
     }
-    elseif ($message->recipient instanceof User) {
+    elseif ($message->recipient && $message->recipient->getOriginalEntity() instanceof User) {
       // Send to the user in the user's preferred language.
       $to = $message->recipient->mail;
       $recipient_langcode = user_preferred_langcode($message->recipient);
diff --git a/core/modules/file/lib/Drupal/file/Tests/FileFieldWidgetTest.php b/core/modules/file/lib/Drupal/file/Tests/FileFieldWidgetTest.php
index 05b0cad..96d1b8d 100644
--- a/core/modules/file/lib/Drupal/file/Tests/FileFieldWidgetTest.php
+++ b/core/modules/file/lib/Drupal/file/Tests/FileFieldWidgetTest.php
@@ -242,7 +242,7 @@ function testPrivateFileComment() {
     $user = $this->drupalCreateUser(array('access comments'));
 
     // Grant the admin user required comment permissions.
-    user_role_grant_permissions(key($this->admin_user->roles), array('administer comment fields'));
+    user_role_grant_permissions($this->admin_user->roles[1], array('administer comment fields'));
 
     // Revoke access comments permission from anon user, grant post to
     // authenticated.
diff --git a/core/modules/node/node.module b/core/modules/node/node.module
index 4c7392b..edd56d5 100644
--- a/core/modules/node/node.module
+++ b/core/modules/node/node.module
@@ -2527,7 +2527,7 @@ function node_access($op, $node, $account = NULL, $langcode = NULL) {
   // Make sure that if an account is passed, that it is a fully loaded user
   // object.
   if ($account && !($account instanceof User)) {
-    $account = user_load($account->uid);
+    $account = entity_load('user', $account->uid);
   }
 
   $method = $op . 'Access';
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityAccessTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityAccessTest.php
index 0642032..773cd18 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityAccessTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityAccessTest.php
@@ -82,7 +82,7 @@ function testEntityAccess() {
       'update' => FALSE,
       'delete' => FALSE,
       'view' => FALSE,
-    ), $entity, $custom_user);
+    ), $entity, $custom_user->getOriginalEntity());
   }
 
   /**
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityApiTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityApiTest.php
index 1a8947c..6269bed 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityApiTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityApiTest.php
@@ -7,7 +7,8 @@
 
 namespace Drupal\system\Tests\Entity;
 
-use Drupal\user\Plugin\Core\Entity\User;
+use Drupal\Core\Entity\EntityInterface;
+
 
 /**
  * Tests the basic Entity API.
@@ -50,10 +51,10 @@ public function testCRUD() {
    *
    * @param string $entity_type
    *   The entity type to run the tests with.
-   * @param \Drupal\user\Plugin\Core\Entity\User $user1
+   * @param \Drupal\Core\Entity\EntityInterface $user1
    *   The user to run the tests with.
    */
-  protected function assertCRUD($entity_type, User $user1) {
+  protected function assertCRUD($entity_type, EntityInterface $user1) {
     // Create some test entities.
     $entity = entity_create($entity_type, array('name' => 'test', 'user_id' => $user1->uid));
     $entity->save();
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php
index 3c5679b..7cfc95c 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityFieldTest.php
@@ -117,19 +117,19 @@ protected function assertReadWrite($entity_type) {
     $this->assertTrue($entity->user_id[0] instanceof FieldItemInterface, format_string('%entity_type: Field item implements interface', array('%entity_type' => $entity_type)));
 
     $this->assertEqual($this->entity_user->uid, $entity->user_id->target_id, format_string('%entity_type: User id can be read.', array('%entity_type' => $entity_type)));
-    $this->assertEqual($this->entity_user->name, $entity->user_id->entity->name, format_string('%entity_type: User name can be read.', array('%entity_type' => $entity_type)));
+    $this->assertEqual($this->entity_user->name, $entity->user_id->entity->name->value, format_string('%entity_type: User name can be read.', array('%entity_type' => $entity_type)));
 
     // Change the assigned user by entity.
     $new_user = $this->createUser();
     $entity->user_id->entity = $new_user;
     $this->assertEqual($new_user->uid, $entity->user_id->target_id, format_string('%entity_type: Updated user id can be read.', array('%entity_type' => $entity_type)));
-    $this->assertEqual($new_user->name, $entity->user_id->entity->name, format_string('%entity_type: Updated user name value can be read.', array('%entity_type' => $entity_type)));
+    $this->assertEqual($new_user->name, $entity->user_id->entity->name->value, format_string('%entity_type: Updated user name value can be read.', array('%entity_type' => $entity_type)));
 
     // Change the assigned user by id.
     $new_user = $this->createUser();
     $entity->user_id->target_id = $new_user->uid;
     $this->assertEqual($new_user->uid, $entity->user_id->target_id, format_string('%entity_type: Updated user id can be read.', array('%entity_type' => $entity_type)));
-    $this->assertEqual($new_user->name, $entity->user_id->entity->name, format_string('%entity_type: Updated user name value can be read.', array('%entity_type' => $entity_type)));
+    $this->assertEqual($new_user->name, $entity->user_id->entity->name->value, format_string('%entity_type: Updated user name value can be read.', array('%entity_type' => $entity_type)));
 
     // Try unsetting a field.
     $entity->name->value = NULL;
@@ -217,7 +217,7 @@ protected function assertReadWrite($entity_type) {
     ));
     $this->assertEqual($this->entity_name, $entity->name->value, format_string('%entity_type: Name value can be read.', array('%entity_type' => $entity_type)));
     $this->assertEqual($this->entity_user->uid, $entity->user_id->target_id, format_string('%entity_type: User id can be read.', array('%entity_type' => $entity_type)));
-    $this->assertEqual($this->entity_user->name, $entity->user_id->entity->name, format_string('%entity_type: User name can be read.', array('%entity_type' => $entity_type)));
+    $this->assertEqual($this->entity_user->name, $entity->user_id->entity->name->value, format_string('%entity_type: User name can be read.', array('%entity_type' => $entity_type)));
     $this->assertEqual($this->entity_field_text, $entity->field_test_text->value, format_string('%entity_type: Text field can be read.', array('%entity_type' => $entity_type)));
 
     // Test copying field values.
@@ -328,7 +328,7 @@ protected function assertSave($entity_type) {
     $this->assertEqual(LANGUAGE_NOT_SPECIFIED, $entity->langcode->value, format_string('%entity_type: Language code can be read.', array('%entity_type' => $entity_type)));
     $this->assertEqual(language_load(LANGUAGE_NOT_SPECIFIED), $entity->langcode->language, format_string('%entity_type: Language object can be read.', array('%entity_type' => $entity_type)));
     $this->assertEqual($this->entity_user->uid, $entity->user_id->target_id, format_string('%entity_type: User id can be read.', array('%entity_type' => $entity_type)));
-    $this->assertEqual($this->entity_user->name, $entity->user_id->entity->name, format_string('%entity_type: User name can be read.', array('%entity_type' => $entity_type)));
+    $this->assertEqual($this->entity_user->name, $entity->user_id->entity->name->value, format_string('%entity_type: User name can be read.', array('%entity_type' => $entity_type)));
     $this->assertEqual($this->entity_field_text, $entity->field_test_text->value, format_string('%entity_type: Text field can be read.', array('%entity_type' => $entity_type)));
   }
 
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityUnitTestBase.php b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityUnitTestBase.php
index b747e79..1209e7b 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/EntityUnitTestBase.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/EntityUnitTestBase.php
@@ -51,7 +51,7 @@ protected function createUser($values = array(), $permissions = array()) {
       ));
       $role->save();
       user_role_grant_permissions($role->id(), $permissions);
-      $values['roles'][$role->id()] = $role->id();
+      $values['roles'][] = $role->id();
     }
 
     $account = entity_create('user', $values + array(
diff --git a/core/modules/system/lib/Drupal/system/Tests/Entity/FieldAccessTest.php b/core/modules/system/lib/Drupal/system/Tests/Entity/FieldAccessTest.php
index 09e7a7a..4116b4e 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Entity/FieldAccessTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Entity/FieldAccessTest.php
@@ -70,12 +70,12 @@ function testFieldAccess() {
     $values = array('name' => 'test');
     $account = entity_create('user', $values);
 
-    $this->assertFalse($entity->field_test_text->access('view', $account), 'Access to the field was denied.');
+    $this->assertFalse($entity->field_test_text->access('view', $account->getOriginalEntity()), 'Access to the field was denied.');
 
     $entity->field_test_text = 'access alter value';
-    $this->assertFalse($entity->field_test_text->access('view', $account), 'Access to the field was denied.');
+    $this->assertFalse($entity->field_test_text->access('view', $account->getOriginalEntity()), 'Access to the field was denied.');
 
     $entity->field_test_text = 'standard value';
-    $this->assertTrue($entity->field_test_text->access('view', $account), 'Access to the field was granted.');
+    $this->assertTrue($entity->field_test_text->access('view', $account->getOriginalEntity()), 'Access to the field was granted.');
   }
 }
diff --git a/core/modules/user/lib/Drupal/user/ProfileFormController.php b/core/modules/user/lib/Drupal/user/ProfileFormController.php
index c2b139d..bc36fbd 100644
--- a/core/modules/user/lib/Drupal/user/ProfileFormController.php
+++ b/core/modules/user/lib/Drupal/user/ProfileFormController.php
@@ -30,6 +30,15 @@ protected function actions(array $form, array &$form_state) {
   }
 
   /**
+   * Overrides Drupal\Core\Entity\EntityFormController::buildEntity().
+   */
+  public function buildEntity(array $form, array &$form_state) {
+    // Change the roles array to a list of enabled roles.
+    $form_state['values']['roles'] = array_keys(array_filter($form_state['values']['roles']));
+    return parent::buildEntity($form, $form_state);
+  }
+
+  /**
    * Overrides Drupal\Core\Entity\EntityFormController::submit().
    */
   public function submit(array $form, array &$form_state) {
diff --git a/core/modules/user/lib/Drupal/user/Tests/UserAdminTest.php b/core/modules/user/lib/Drupal/user/Tests/UserAdminTest.php
index 3b83b52..0769fff 100644
--- a/core/modules/user/lib/Drupal/user/Tests/UserAdminTest.php
+++ b/core/modules/user/lib/Drupal/user/Tests/UserAdminTest.php
@@ -60,8 +60,8 @@ function testUserAdmin() {
 
     // Filter the users by role. Grab the system-generated role name for User C.
     $roles = $user_c->roles;
-    unset($roles[DRUPAL_AUTHENTICATED_RID]);
-    $edit['role'] = key($roles);
+    unset($roles[array_search(DRUPAL_AUTHENTICATED_RID, $roles)]);
+    $edit['role'] = reset($roles);
     $this->drupalPost('admin/people', $edit, t('Refine'));
 
     // Check if the correct users show up when filtered by role.
diff --git a/core/modules/user/lib/Drupal/user/Tests/UserPermissionsTest.php b/core/modules/user/lib/Drupal/user/Tests/UserPermissionsTest.php
index 2455b10..3fc3b4b 100644
--- a/core/modules/user/lib/Drupal/user/Tests/UserPermissionsTest.php
+++ b/core/modules/user/lib/Drupal/user/Tests/UserPermissionsTest.php
@@ -28,8 +28,8 @@ function setUp() {
 
     // Find the new role ID.
     $all_rids = $this->admin_user->roles;
-    unset($all_rids[DRUPAL_AUTHENTICATED_RID]);
-    $this->rid = key($all_rids);
+    unset($all_rids[array_search(DRUPAL_AUTHENTICATED_RID, $all_rids)]);
+    $this->rid = reset($all_rids);
   }
 
   /**
diff --git a/core/modules/user/lib/Drupal/user/UserStorageController.php b/core/modules/user/lib/Drupal/user/UserStorageController.php
index b0eef51..20978c8 100644
--- a/core/modules/user/lib/Drupal/user/UserStorageController.php
+++ b/core/modules/user/lib/Drupal/user/UserStorageController.php
@@ -65,6 +65,12 @@ public function save(EntityInterface $entity) {
       $entity->uid->value = db_next_id(db_query('SELECT MAX(uid) FROM {users}')->fetchField());
       $entity->enforceIsNew();
     }
+
+    // There are some cases that pre-set ->original for performance. Make sure
+    // original is not a BC decorator.
+    if ($entity->original instanceof \Drupal\Core\Entity\EntityBCDecorator) {
+      $entity->original = $entity->original->getOriginalEntity();
+    }
     parent::save($entity);
   }
 
@@ -148,7 +154,7 @@ protected function postSave(EntityInterface $entity, $update) {
       if ($entity->status->value != $entity->original->status->value) {
         // The user's status is changing; conditionally send notification email.
         $op = $entity->status->value == 1 ? 'status_activated' : 'status_blocked';
-        _user_mail_notify($op, $entity);
+        _user_mail_notify($op, $entity->getBCEntity());
       }
     }
     else {
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 1faa9ce..54aec69 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -177,7 +177,7 @@ function user_uri($user) {
  * @see user_format_name()
  */
 function user_label($entity_type, $entity) {
-  return user_format_name($entity);
+  return user_format_name($entity->getBCEntity());
 }
 
 /**
@@ -343,7 +343,7 @@ function user_load($uid, $reset = FALSE) {
  */
 function user_load_by_mail($mail) {
   $users = entity_load_multiple_by_properties('user', array('mail' => $mail));
-  return reset($users)->getBCEntity();
+  return $users ? reset($users)->getBCEntity() : FALSE;
 }
 
 /**
@@ -359,7 +359,7 @@ function user_load_by_mail($mail) {
  */
 function user_load_by_name($name) {
   $users = entity_load_multiple_by_properties('user', array('name' => $name));
-  return reset($users)->getBCEntity();
+  return $users ? reset($users)->getBCEntity() : FALSE;
 }
 
 /**
@@ -440,7 +440,7 @@ function user_role_permissions($roles) {
 
   $role_permissions = $fetch = array();
 
-  foreach ($roles as $rid => $name) {
+  foreach ($roles as $rid) {
     if (isset($cache[$rid])) {
       $role_permissions[$rid] = $cache[$rid];
     }
@@ -491,6 +491,9 @@ function user_access($string, $account = NULL) {
     $account = $user;
   }
 
+  // Make sure we are working with the BC decorator.
+  $account = $account instanceof User ? $account->getBCEntity() : $account;
+
   // User #1 has all privileges:
   if ($account->uid == 1) {
     return TRUE;
@@ -2341,6 +2344,7 @@ function theme_user_signature($variables) {
  */
 function user_preferred_langcode($account, $type = NULL, $default = NULL) {
   $language_list = language_list();
+  $account = $account->getBCEntity();
   if (isset($type)) {
     $preferred_langcode = $account->{'preferred_' . $type . '_langcode'};
   }
diff --git a/core/modules/user/user.pages.inc b/core/modules/user/user.pages.inc
index 140b767..4e57868 100644
--- a/core/modules/user/user.pages.inc
+++ b/core/modules/user/user.pages.inc
@@ -67,7 +67,7 @@ function user_pass_submit($form, &$form_state) {
 
   $account = $form_state['values']['account'];
   // Mail one time login URL and instructions using current language.
-  $mail = _user_mail_notify('password_reset', $account, $language_interface->langcode);
+  $mail = _user_mail_notify('password_reset', $account->getBCEntity(), $language_interface->langcode);
   if (!empty($mail)) {
     watchdog('user', 'Password reset instructions mailed to %name at %email.', array('%name' => $account->name, '%email' => $account->mail));
     drupal_set_message(t('Further instructions have been sent to your e-mail address.'));
diff --git a/core/modules/views/lib/Drupal/views/Tests/Plugin/AccessTest.php b/core/modules/views/lib/Drupal/views/Tests/Plugin/AccessTest.php
index b4c5118..fcbddcb 100644
--- a/core/modules/views/lib/Drupal/views/Tests/Plugin/AccessTest.php
+++ b/core/modules/views/lib/Drupal/views/Tests/Plugin/AccessTest.php
@@ -37,11 +37,12 @@ protected function setUp() {
 
     $this->admin_user = $this->drupalCreateUser(array('access all views'));
     $this->web_user = $this->drupalCreateUser();
-    $this->web_role = current($this->web_user->roles);
+    $this->web_role = $this->web_user->roles[0];
 
     $this->normal_role = $this->drupalCreateRole(array());
     $this->normal_user = $this->drupalCreateUser(array('views_test_data test permission'));
-    $this->normal_user->roles[$this->normal_role] = $this->normal_role;
+    // @todo: How to add a new item to the roles field list. 
+    $this->normal_user->getOriginalEntity()->roles[2]->value = $this->normal_role;
     // @todo when all the plugin information is cached make a reset function and
     // call it here.
   }