diff -u b/core/modules/config/lib/Drupal/config/Controller/ConfigController.php b/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
--- b/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
+++ b/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
@@ -120,15 +120,15 @@
 
     $build = array();
 
-    $build['#title'] = t('View changes of @config_file', array('@config_file' => $source_name));
+    $build['#title'] = $this->t('View changes of @config_file', array('@config_file' => $source_name));
     // Add the CSS for the inline diff.
     $build['#attached']['css'][] = drupal_get_path('module', 'system') . '/css/system.diff.css';
 
     $build['diff'] = array(
       '#type' => 'table',
       '#header' => array(
-        array('data' => t('Old'), 'colspan' => '2'),
-        array('data' => t('New'), 'colspan' => '2'),
+        array('data' => $this->t('Old'), 'colspan' => '2'),
+        array('data' => $this->t('New'), 'colspan' => '2'),
       ),
       '#rows' => $formatter->format($diff),
     );
@@ -161,12 +161,12 @@
     $build['#attached']['css'][] = drupal_get_path('module', 'system') . '/css/system.diff.css';
 
     if ($storage == 'active') {
-      $build['#title'] = t('View changes between snapshot and active configuration.');
+      $build['#title'] = $this->t('View changes between snapshot and active configuration.');
       $used_storage = $this->targetStorage;
       $compare_button = $this->l($this->t('Compare snapshot with staging storage'), 'config.snapshot_diff', array('storage' => 'staging'), array('attributes' => array('class' => array('button'))));
     }
     else {
-      $build['#title'] = t('View changes between snapshot and staging configuration.');
+      $build['#title'] = $this->t('View changes between snapshot and staging configuration.');
       $used_storage = $this->sourceStorage;
       $compare_button = $this->l($this->t('Compare snapshot with active storage'), 'config.snapshot_diff', array('storage' => 'active'), array('attributes' => array('class' => array('button'))));
     }
@@ -192,8 +192,8 @@
             '#prefix' => '<h3>' . $name . '</h3>',
             '#type' => 'table',
             '#header' => array(
-              array('data' => t('Snapshot'), 'colspan' => '2'),
-              array('data' => ($storage == 'active') ? t('Active storage') : t('Staging storage'), 'colspan' => '2'),
+              array('data' => $this->t('Snapshot'), 'colspan' => '2'),
+              array('data' => ($storage == 'active') ? $this->t('Active storage') : $this->t('Staging storage'), 'colspan' => '2'),
             ),
             '#rows' => $formatter->format($diff),
           );
diff -u b/core/modules/config/lib/Drupal/config/Form/ConfigSync.php b/core/modules/config/lib/Drupal/config/Form/ConfigSync.php
--- b/core/modules/config/lib/Drupal/config/Form/ConfigSync.php
+++ b/core/modules/config/lib/Drupal/config/Form/ConfigSync.php
@@ -168,7 +168,7 @@
 
     // Verify that we have an initial snapshot that matches the active
     // configuration.
-    if ($active_snapshot_comparer->createChangelist()->hasChanges()) {
+    if (empty($form_state['input']) && $active_snapshot_comparer->createChangelist()->hasChanges()) {
       drupal_set_message($this->t('Changes have been made to your active configuration, which might be lost on the next import attempt. You can find and review the differences between snapshot and active/staging storage here: <a href="@link">Compare snapshot and active/staging storage</a>.', array(
         '@link' => $this->url('config.snapshot_diff', array('storage' => 'active')))), 'warning');
 
diff -u b/core/modules/config/lib/Drupal/config/Tests/ConfigExportImportUITest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigExportImportUITest.php
--- b/core/modules/config/lib/Drupal/config/Tests/ConfigExportImportUITest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigExportImportUITest.php
@@ -128,23 +128,34 @@
     $this->assertEqual(\Drupal::config('system.site')->get('slogan'), $this->newSlogan);
 
+    $this->drupalGet('node/add');
+    $this->assertFieldByName("{$this->field->name}[0][value]", '', 'Widget is displayed');
+  }
+
+  /**
+   * Tests a warning appears when unsynchronized changes exist..
+   */
+  public function testImportWarning() {
+    $new_slogan = $this->randomName(16);
+    \Drupal::config('system.site')
+      ->set('slogan', $new_slogan)
+      ->save();
+
+    $this->drupalGet('admin/config/development/configuration');
+
     $this->assertText('Changes have been made to your active configuration, which might be lost on the next import attempt. ' .
       'You can find and review the differences between snapshot and active/staging storage here');
 
-    $changed_slogan = $this->randomName(16);
+    $this->drupalGet('admin/config/development/configuration/full/import');
 
-    \Drupal::config('system.site')
-      ->set('slogan', $changed_slogan)
-      ->save();
+    $this->assertText('Changes have been made to your active configuration, which might be lost on the next import attempt. ' .
+      'You can find and review the differences between snapshot and active/staging storage here');
 
     $this->clickLink('Compare snapshot and active/staging storage');
     $this->assertText('View changes between snapshot and active configuration');
     $this->assertText('system.site');
     $this->assertText('Active storage');
-    $this->assertText($changed_slogan, "Changed slogan $changed_slogan found when viewing changes.");
+    $this->assertText($new_slogan, "New slogan $new_slogan found when viewing changes.");
     $this->clickLink('Compare snapshot with staging storage');
     $this->assertText('View changes between snapshot and staging configuration');
-
-    $this->drupalGet('node/add');
-    $this->assertFieldByName("{$this->field->name}[0][value]", '', 'Widget is displayed');
   }
 }