diff --git a/js/ui/extensionDownloader.js b/js/ui/extensionDownloader.js
index 2ae64ea44..25145564d 100644
--- a/js/ui/extensionDownloader.js
+++ b/js/ui/extensionDownloader.js
@@ -120,7 +120,10 @@ function downloadExtensionUpdate(uuid) {
 function checkForUpdates() {
     let metadatas = {};
     Main.extensionManager.getUuids().forEach(uuid => {
-        metadatas[uuid] = Main.extensionManager.lookup(uuid).metadata;
+        let extension = Main.extensionManager.lookup(uuid);
+        if (extension.type !== ExtensionUtils.ExtensionType.PER_USER)
+            return;
+        metadatas[uuid] = extension.metadata;
     });
 
     let params = { shell_version: Config.PACKAGE_VERSION,