diff --git a/js/components/ascribe_uploader/ascribe_file_drag_and_drop/file_drag_and_drop.js b/js/components/ascribe_uploader/ascribe_file_drag_and_drop/file_drag_and_drop.js
index b6b5b218..aedfe1a3 100644
--- a/js/components/ascribe_uploader/ascribe_file_drag_and_drop/file_drag_and_drop.js
+++ b/js/components/ascribe_uploader/ascribe_file_drag_and_drop/file_drag_and_drop.js
@@ -211,7 +211,7 @@ let FileDragAndDrop = React.createClass({
              * For our self defined input, we can reuse those declarations to restrict which files
              * the user can pick from his hard drive.
              */
-            if(validation && validation.allowedExtensions.length > 0) {
+            if(validation && validation.allowedExtensions && validation.allowedExtensions.length > 0) {
                 // add a dot in front of the extension
                 let prefixedAllowedExtensions = validation.allowedExtensions.map((ext) => '.' + ext);