diff -u b/core/modules/locale/lib/Drupal/locale/Form/ImportForm.php b/core/modules/locale/lib/Drupal/locale/Form/ImportForm.php
--- b/core/modules/locale/lib/Drupal/locale/Form/ImportForm.php
+++ b/core/modules/locale/lib/Drupal/locale/Form/ImportForm.php
@@ -159,7 +159,7 @@
    */
   public function submitForm(array &$form, array &$form_state) {
     // Ensure we have the file uploaded.
-    if ($file = file_save_upload('file', $form_state, $form['file']['#upload_validators'], 'translations://', 0)) {
+    if ($file = file_save_upload('file', $form['file']['#upload_validators'], 'translations://', 0)) {
 
       // Add language, if not yet supported.
       $language = language_load($form_state['values']['langcode']);