diff --git a/classes/Modules/Api/Controller/Version1/FileController.php b/classes/Modules/Api/Controller/Version1/FileController.php
index ad88cc26e..9fab4c484 100644
--- a/classes/Modules/Api/Controller/Version1/FileController.php
+++ b/classes/Modules/Api/Controller/Version1/FileController.php
@@ -124,8 +124,8 @@ public function createAction()
             throw new BadRequestException('Required property "file_content" is missing.');
         }
 
-        if (is_array($input['stichwoerter'])) {
-            $stichwoerter = array();
+        $stichwoerter = array();
+        if (isset($input['stichwoerter']) && is_array($input['stichwoerter'])) {
             $erp = $this->legacyApi->app->erp;
             $DB = $this->legacyApi->app->DB;
             foreach ($input['stichwoerter'] as $stichwort_input) {