diff --git a/core/modules/config/lib/Drupal/config/Form/ConfigSingleImportForm.php b/core/modules/config/lib/Drupal/config/Form/ConfigSingleImportForm.php
index c1e00a0..5334765 100644
--- a/core/modules/config/lib/Drupal/config/Form/ConfigSingleImportForm.php
+++ b/core/modules/config/lib/Drupal/config/Form/ConfigSingleImportForm.php
@@ -231,12 +231,16 @@ public function submitForm(array &$form, array &$form_state) {
     }
     // For a config entity, create a new entity and save it.
     else {
-      $entity = $this->entityManager
-        ->getStorageController($this->data['config_type'])
-        ->create($this->data['import']);
-      $entity->save();
-
-      drupal_set_message($this->t('The @entity_type %label was imported.', array('@entity_type' => $entity->entityType(), '%label' => $entity->label())));
+      try {
+        $entity = $this->entityManager
+          ->getStorageController($this->data['config_type'])
+          ->create($this->data['import']);
+        $entity->save();
+        drupal_set_message($this->t('The @entity_type %label was imported.', array('@entity_type' => $entity->entityType(), '%label' => $entity->label())));
+      }
+      catch (\Exception $e) {
+        drupal_set_message($e->getMessage(), 'error');
+      }
     }
   }
 
diff --git a/core/modules/field/lib/Drupal/field/FieldInstanceStorageController.php b/core/modules/field/lib/Drupal/field/FieldInstanceStorageController.php
index 2b4ef46..d74db76 100644
--- a/core/modules/field/lib/Drupal/field/FieldInstanceStorageController.php
+++ b/core/modules/field/lib/Drupal/field/FieldInstanceStorageController.php
@@ -114,10 +114,10 @@ public function importDelete($name, Config $new_config, Config $old_config) {
   public function loadByProperties(array $conditions = array()) {
     // Include instances of inactive fields if specified in the
     // $conditions parameters.
-    $include_inactive = $conditions['include_inactive'];
+    $include_inactive = isset($conditions['include_inactive']) ? $conditions['include_inactive'] : FALSE;
     unset($conditions['include_inactive']);
     // Include deleted instances if specified in the $conditions parameters.
-    $include_deleted = $conditions['include_deleted'];
+    $include_deleted = isset($conditions['include_deleted']) ? $conditions['include_deleted'] : FALSE;
     unset($conditions['include_deleted']);
 
     // Get instances stored in configuration.
diff --git a/core/modules/field/lib/Drupal/field/FieldStorageController.php b/core/modules/field/lib/Drupal/field/FieldStorageController.php
index fff0df7..b18ffe3 100644
--- a/core/modules/field/lib/Drupal/field/FieldStorageController.php
+++ b/core/modules/field/lib/Drupal/field/FieldStorageController.php
@@ -96,10 +96,10 @@ public static function createInstance(ContainerInterface $container, $entity_typ
   public function loadByProperties(array $conditions = array()) {
     // Include instances of inactive fields if specified in the
     // $conditions parameters.
-    $include_inactive = $conditions['include_inactive'];
+    $include_inactive = isset($conditions['include_inactive']) ? $conditions['include_inactive'] : FALSE;
     unset($conditions['include_inactive']);
     // Include deleted instances if specified in the $conditions parameters.
-    $include_deleted = $conditions['include_deleted'];
+    $include_deleted = isset($conditions['include_deleted']) ? $conditions['include_deleted'] : FALSE;
     unset($conditions['include_deleted']);
 
     // Get fields stored in configuration.