diff --git a/js/misc/extensionUtils.js b/js/misc/extensionUtils.js
index b7b6282f0..9e70e265f 100644
--- a/js/misc/extensionUtils.js
+++ b/js/misc/extensionUtils.js
@@ -132,6 +132,7 @@ function createExtensionObject(uuid, dir, type) {
     extension.type = type;
     extension.dir = dir;
     extension.path = dir.get_path();
+    extension.error = '';
     extension.hasPrefs = dir.get_child('prefs.js').query_exists(null);
 
     extensions[uuid] = extension;