diff --git a/core/modules/config/config.routing.yml b/core/modules/config/config.routing.yml
index bd0d5c5..9349f97 100644
--- a/core/modules/config/config.routing.yml
+++ b/core/modules/config/config.routing.yml
@@ -53,3 +53,10 @@ config.export_single:
     config_name: NULL
   requirements:
     _permission: 'export configuration'
+
+config.snapshot_diff:
+  path: '/admin/config/development/configuration/sync/snapshot-diff'
+  defaults:
+    _content: '\Drupal\config\Controller\ConfigController::snapshotDiff'
+  requirements:
+    _permission: 'import configuration'
diff --git a/core/modules/config/lib/Drupal/config/Controller/ConfigController.php b/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
index 18f6287..98a3ca4 100644
--- a/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
+++ b/core/modules/config/lib/Drupal/config/Controller/ConfigController.php
@@ -14,6 +14,7 @@
 use Drupal\system\FileDownloadController;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\Request;
+use Drupal\Core\Config\StorageComparer;
 
 /**
  * Returns responses for config module routes.
@@ -55,6 +56,7 @@ public static function create(ContainerInterface $container) {
     return new static(
       $container->get('config.storage'),
       $container->get('config.storage.staging'),
+      $container->get('config.storage.snapshot'),
       $container->get('config.manager'),
       new FileDownloadController()
     );
@@ -70,9 +72,10 @@ public static function create(ContainerInterface $container) {
    * @param \Drupal\system\FileDownloadController $file_download_controller
    *   The file download controller.
    */
-  public function __construct(StorageInterface $target_storage, StorageInterface $source_storage, ConfigManagerInterface $config_manager, FileDownloadController $file_download_controller) {
+  public function __construct(StorageInterface $target_storage, StorageInterface $source_storage, StorageInterface $snapshot_storage, ConfigManagerInterface $config_manager, FileDownloadController $file_download_controller) {
     $this->targetStorage = $target_storage;
     $this->sourceStorage = $source_storage;
+    $this->snapshotStorage = $snapshot_storage;
     $this->configManager = $config_manager;
     $this->fileDownloadController = $file_download_controller;
   }
@@ -136,4 +139,58 @@ public function diff($config_file) {
 
     return $build;
   }
+
+  /**
+   * Show diff of snapshot and active/staging storage.
+   *
+   * @return string
+   *   Table showing a two-way diff between the snapshot and
+   *   active/staged configuration.
+   */
+  public function snapshotDiff() {
+    $build = array();
+
+    $build['#title'] = t('View changes between snapshot and active/staging configuration.');
+    // Add the CSS for the inline diff.
+    $build['#attached']['css'][] = drupal_get_path('module', 'system') . '/css/system.diff.css';
+
+    $active = $this->targetStorage;
+    $staging = $this->sourceStorage;
+    $snapshot = $this->snapshotStorage;
+
+    $active_snapshot_comparer = new StorageComparer($active, $snapshot);
+
+    $active_snapshot_comparer->createChangelist();
+    $changelist = $active_snapshot_comparer->getChangelist();
+
+    // Show changes for each configuration object.
+    foreach ($changelist as $op) {
+      foreach ($op as $name) {
+        $diff = $this->configManager->diff($active, $staging, $name);
+        $formatter = new \DrupalDiffFormatter();
+        $formatter->show_header = FALSE;
+
+        $build[$name] = array(
+          '#type' => 'table',
+          '#header' => array(
+            array('data' => $name, 'colspan' => '4'),
+          ),
+          '#rows' => $formatter->format($diff),
+        );
+      }
+    }
+
+    $build['back'] = array(
+      '#type' => 'link',
+      '#attributes' => array(
+        'class' => array(
+          'dialog-cancel',
+        ),
+      ),
+      '#title' => "Back to 'Synchronize configuration' page.",
+      '#href' => 'admin/config/development/configuration',
+    );
+
+    return $build;
+  }
 }
diff --git a/core/modules/config/lib/Drupal/config/Form/ConfigImportForm.php b/core/modules/config/lib/Drupal/config/Form/ConfigImportForm.php
index bb5f4ed..d881c33 100644
--- a/core/modules/config/lib/Drupal/config/Form/ConfigImportForm.php
+++ b/core/modules/config/lib/Drupal/config/Form/ConfigImportForm.php
@@ -11,6 +11,7 @@
 use Drupal\Core\Form\FormBase;
 use Drupal\Component\Archiver\ArchiveTar;
 use Symfony\Component\DependencyInjection\ContainerInterface;
+use Drupal\Core\Config\StorageComparer;
 
 /**
  * Defines the configuration import form.
@@ -30,8 +31,10 @@ class ConfigImportForm extends FormBase {
    * @param \Drupal\Core\Config\StorageInterface $config_storage
    *   The configuration storage.
    */
-  public function __construct(StorageInterface $config_storage) {
+  public function __construct(StorageInterface $config_storage, StorageInterface $config_storage_snapshot, StorageInterface $config_storage_active) {
     $this->configStorage = $config_storage;
+    $this->configStorageSnapshot = $config_storage_snapshot;
+    $this->configStorageActive = $config_storage_active;
   }
 
   /**
@@ -39,7 +42,9 @@ public function __construct(StorageInterface $config_storage) {
    */
   public static function create(ContainerInterface $container) {
     return new static(
-      $container->get('config.storage.staging')
+      $container->get('config.storage.staging'),
+      $container->get('config.storage.snapshot'),
+      $container->get('config.storage')
     );
   }
 
@@ -54,6 +59,15 @@ public function getFormId() {
    * {@inheritdoc}
    */
   public function buildForm(array $form, array &$form_state) {
+    $active_snapshot_comparer = new StorageComparer($this->configStorageActive, $this->configStorageSnapshot);
+
+    // Verify that we have an initial snapshot that matches the active
+    // configuration.
+    if ($active_snapshot_comparer->createChangelist()->hasChanges()) {
+      drupal_set_message($this->t('Changes have been made since last import, 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->urlGenerator()->generateFromRoute('config.snapshot_diff'))), 'warning');
+    }
+
     $form['description'] = array(
       '#markup' => '<p>' . $this->t('Use the upload button below.') . '</p>',
     );
diff --git a/core/modules/config/lib/Drupal/config/Form/ConfigSync.php b/core/modules/config/lib/Drupal/config/Form/ConfigSync.php
index c600001..e43ab1c 100644
--- a/core/modules/config/lib/Drupal/config/Form/ConfigSync.php
+++ b/core/modules/config/lib/Drupal/config/Form/ConfigSync.php
@@ -73,6 +73,14 @@ class ConfigSync extends FormBase {
   protected $typedConfigManager;
 
   /**
+   * The snapshot configuration object.
+   *
+   * @var \Drupal\Core\Config\StorageInterface
+   */
+  protected $snapshotStorage;
+
+
+  /**
    * Constructs the object.
    *
    * @param \Drupal\Core\Config\StorageInterface $sourceStorage
@@ -90,7 +98,7 @@ class ConfigSync extends FormBase {
    * @param \Drupal\Core\Config\TypedConfigManager $typed_config
    *   The typed configuration manager.
    */
-  public function __construct(StorageInterface $sourceStorage, StorageInterface $targetStorage, LockBackendInterface $lock, EventDispatcherInterface $event_dispatcher, ConfigManagerInterface $config_manager, UrlGeneratorInterface $url_generator, TypedConfigManager $typed_config) {
+  public function __construct(StorageInterface $sourceStorage, StorageInterface $targetStorage, LockBackendInterface $lock, EventDispatcherInterface $event_dispatcher, ConfigManagerInterface $config_manager, UrlGeneratorInterface $url_generator, TypedConfigManager $typed_config, StorageInterface $snapshotStorage) {
     $this->sourceStorage = $sourceStorage;
     $this->targetStorage = $targetStorage;
     $this->lock = $lock;
@@ -98,6 +106,7 @@ public function __construct(StorageInterface $sourceStorage, StorageInterface $t
     $this->configManager = $config_manager;
     $this->urlGenerator = $url_generator;
     $this->typedConfigManager = $typed_config;
+    $this->snapshotStorage = $snapshotStorage;
   }
 
   /**
@@ -111,7 +120,8 @@ public static function create(ContainerInterface $container) {
       $container->get('event_dispatcher'),
       $container->get('config.manager'),
       $container->get('url_generator'),
-      $container->get('config.typed')
+      $container->get('config.typed'),
+      $container->get('config.storage.snapshot')
     );
   }
 
@@ -126,6 +136,15 @@ public function getFormId() {
    * {@inheritdoc}
    */
   public function buildForm(array $form, array &$form_state) {
+    $active_snapshot_comparer = new StorageComparer($this->targetStorage, $this->snapshotStorage);
+
+    // Verify that we have an initial snapshot that matches the active
+    // configuration.
+    if ($active_snapshot_comparer->createChangelist()->hasChanges()) {
+      drupal_set_message($this->t('Changes have been made since last import, 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->urlGenerator()->generateFromRoute('config.snapshot_diff'))), 'warning');
+    }
+
     $form['actions'] = array('#type' => 'actions');
     $form['actions']['submit'] = array(
       '#type' => 'submit',