diff --git a/core/modules/menu_link/lib/Drupal/menu_link/MenuLinkStorageController.php b/core/modules/menu_link/lib/Drupal/menu_link/MenuLinkStorageController.php
index de04d97..8b58ad7 100644
--- a/core/modules/menu_link/lib/Drupal/menu_link/MenuLinkStorageController.php
+++ b/core/modules/menu_link/lib/Drupal/menu_link/MenuLinkStorageController.php
@@ -81,7 +81,10 @@ protected function attachLoad(&$menu_links, $load_revision = FALSE) {
     if ($routes) {
       $route_objects = drupal_container()->get('router.route_provider')->getRoutesByNames($routes);
       foreach ($routes as $entity_id => $route) {
-        $menu_links[$entity_id]->setRouteObject($route_objects[$route]);
+        // Not all stored routes will be valid on loaded.
+        if (isset($route_objects[$route])) {
+          $menu_links[$entity_id]->setRouteObject($route_objects[$route]);
+        }
       }
     }