diff --git a/apps/files/ajax/download.php b/apps/files/ajax/download.php
index b2e144c4b8f5540859dd2e37573c40bb0d9fc3af..368257b95cdf8a5de33a4fc46cb3f5f3a4ec9a4e 100644
--- a/apps/files/ajax/download.php
+++ b/apps/files/ajax/download.php
@@ -25,8 +25,8 @@
 OCP\User::checkLoggedIn();
 \OC::$server->getSession()->close();
 
-$files = $_GET["files"];
-$dir = $_GET["dir"];
+$files = isset($_GET['files']) ? $_GET['files'] : '';
+$dir = isset($_GET['dir']) ? $_GET['dir'] : '';
 
 $files_list = json_decode($files);
 // in case we get only a single file