diff --git a/core/modules/block/src/BlockListBuilder.php b/core/modules/block/src/BlockListBuilder.php
index 3365415..775beca 100644
--- a/core/modules/block/src/BlockListBuilder.php
+++ b/core/modules/block/src/BlockListBuilder.php
@@ -355,20 +355,26 @@ public function validateForm(array &$form, FormStateInterface $form_state) {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
-    $entities = $this->storage->loadMultiple(array_keys($form_state->getValue('blocks')));
-    /** @var \Drupal\block\BlockInterface[] $entities */
-    foreach ($entities as $entity_id => $entity) {
-      $entity_values = $form_state->getValue(array('blocks', $entity_id));
-      $entity->setWeight($entity_values['weight']);
-      $entity->setRegion($entity_values['region']);
-      if ($entity->getRegion() == BlockInterface::BLOCK_REGION_NONE) {
-        $entity->disable();
-      }
-      else {
-        $entity->enable();
+    $blocks = $form_state->getValue('blocks');
+    // Passing an empty value to ::loadMultiple would load all items from the
+    // storage.
+    if (!empty($blocks)) {
+      $entities = $this->storage->loadMultiple(array_keys($blocks));
+      /** @var \Drupal\block\BlockInterface[] $entities */
+      foreach ($entities as $entity_id => $entity) {
+        $entity_values = $form_state->getValue(array('blocks', $entity_id));
+        $entity->setWeight($entity_values['weight']);
+        $entity->setRegion($entity_values['region']);
+        if ($entity->getRegion() == BlockInterface::BLOCK_REGION_NONE) {
+          $entity->disable();
+        }
+        else {
+          $entity->enable();
+        }
+        $entity->save();
       }
-      $entity->save();
     }
+
     drupal_set_message(t('The block settings have been updated.'));
 
     // Remove any previously set block placement.