diff --git a/app/assets/javascripts/editor/editor.js.erb b/app/assets/javascripts/editor/editor.js.erb
index c64ef3ee..4b4c8810 100644
--- a/app/assets/javascripts/editor/editor.js.erb
+++ b/app/assets/javascripts/editor/editor.js.erb
@@ -414,6 +414,9 @@ var CodeOceanEditor = {
     },
 
     isActiveFileRenderable: function () {
+        if (this.active_frame.data() === undefined) {
+            return false;
+        }
         return 'renderable' in this.active_frame.data();
     },