diff --git a/core/modules/user/user.install b/core/modules/user/user.install
index e659970..e9b3e90 100644
--- a/core/modules/user/user.install
+++ b/core/modules/user/user.install
@@ -5,6 +5,7 @@
  * Install, update and uninstall functions for the user module.
  */
 
+use Drupal\Component\Uuid\Uuid;
 use Drupal\Core\Language\Language;
 use Drupal\field\Field;
 
@@ -227,22 +228,25 @@ function user_schema() {
  * Implements hook_install().
  */
 function user_install() {
+  $uuid = new Uuid();
+
   // Insert a row for the anonymous user.
   db_insert('users')
     ->fields(array(
       'uid' => 0,
+      'uuid' => $uuid->generate(),
       'name' => '',
       'mail' => '',
       'langcode' => language_default()->id,
     ))
     ->execute();
 
-  // We need some placeholders here as name and mail are uniques and data is
-  // presumed to be a serialized array. This will be changed by the settings
-  // form in the installer.
+  // We need some placeholders here as name and mail are uniques.
+  // This will be changed by the settings form in the installer.
   db_insert('users')
     ->fields(array(
       'uid' => 1,
+      'uuid' => $uuid->generate(),
       'name' => 'placeholder-for-uid-1',
       'mail' => 'placeholder-for-uid-1',
       'created' => REQUEST_TIME,