diff --git a/wp-includes/nav-menu.php b/wp-includes/nav-menu.php
index 38ef5c89bc..aff8a54373 100644
--- a/wp-includes/nav-menu.php
+++ b/wp-includes/nav-menu.php
@@ -1084,7 +1084,8 @@ function _wp_menus_changed() {
  * @return array Nav menus mapped to new nav menu locations.
  */
 function wp_map_nav_menu_locations( $new_nav_menu_locations, $old_nav_menu_locations ) {
-	$registered_nav_menus = get_registered_nav_menus();
+	$registered_nav_menus   = get_registered_nav_menus();
+	$new_nav_menu_locations = array_intersect_key( $new_nav_menu_locations, $registered_nav_menus );
 
 	// Short-circuit if there are no old nav menu location assignments to map.
 	if ( empty( $old_nav_menu_locations ) ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 8fd15a1129..18fecc2f20 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-beta1-41810';
+$wp_version = '4.9-beta1-41811';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.