diff --git a/core/modules/system/lib/Drupal/system/Tests/Installer/InstallerTranslationTest.php b/core/modules/system/lib/Drupal/system/Tests/Installer/InstallerTranslationTest.php
index 3efe3977f8693fcfae63323220d308e144add8b5..91e5485eb0b6ee69f8def56a808e1aae78a4ab41 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Installer/InstallerTranslationTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Installer/InstallerTranslationTest.php
@@ -35,6 +35,8 @@ protected function setUp() {
 
     // Add the translations directory so we can retrieve German translations.
     $conf['locale.settings']['translation.path'] = drupal_get_path('module', 'simpletest') . '/files/translations';
+    $conf['language_default']['name'] = 'German';
+    $conf['language_default']['id'] = 'de';
 
     // Create the database prefix for this test.
     $this->prepareDatabasePrefix();
@@ -120,6 +122,16 @@ protected function setUp() {
       $config->save();
     }
 
+    // Submit site configuration form.
+    $this->drupalPostForm(NULL, array(
+      'site_mail' => 'admin@test.de',
+      'account[name]' => 'admin',
+      'account[mail]' => 'admin@test.de',
+      'account[pass][pass1]' => '123',
+      'account[pass][pass2]' => '123',
+      'site_default_country' => 'DE',
+    ), $submit_value);
+
     // Use the test mail class instead of the default mail handler class.
     \Drupal::config('system.mail')->set('interface.default', 'Drupal\Core\Mail\VariableLog')->save();
 
diff --git a/core/modules/user/user.install b/core/modules/user/user.install
index 62d9e17dbd0ac3b99d2377ed2220bc69ac053f58..e659970679cb4c755d075154e202746b5ae35b96 100644
--- a/core/modules/user/user.install
+++ b/core/modules/user/user.install
@@ -233,6 +233,7 @@ function user_install() {
       'uid' => 0,
       'name' => '',
       'mail' => '',
+      'langcode' => language_default()->id,
     ))
     ->execute();
 
@@ -246,6 +247,7 @@ function user_install() {
       'mail' => 'placeholder-for-uid-1',
       'created' => REQUEST_TIME,
       'status' => 1,
+      'langcode' => language_default()->id,
     ))
     ->execute();
 }