diff --git a/system/src/Grav/Common/Flex/Types/UserGroups/UserGroupObject.php b/system/src/Grav/Common/Flex/Types/UserGroups/UserGroupObject.php
index b3d7b237f5..8ecee2f1a7 100644
--- a/system/src/Grav/Common/Flex/Types/UserGroups/UserGroupObject.php
+++ b/system/src/Grav/Common/Flex/Types/UserGroups/UserGroupObject.php
@@ -78,7 +78,7 @@ public function authorize(string $action, string $scope = null): ?bool
     public static function groupNames(): array
     {
         $groups = [];
-        $user_groups = Grav::instance()['user_groups'];
+        $user_groups = Grav::instance()['user_groups'] ?? [];
 
         foreach ($user_groups as $key => $group) {
             $groups[$key] = $group->readableName;