url needs to be string

src/vs/workbench/electron-main/update-manager.ts

@@ -10,6 +10,7 @@ import events = require('events');
 
 import electron = require('electron');
 import platform = require('vs/base/common/platform');
+import { isString } from 'vs/base/common/types';
 import env = require('vs/workbench/electron-main/env');
 import settings = require('vs/workbench/electron-main/settings');
 import {Win32AutoUpdaterImpl} from 'vs/workbench/electron-main/auto-updater.win32';
@@ -92,7 +93,7 @@ export class UpdateManager extends events.EventEmitter {
 
 			let data: IUpdate = null;
 
-			if (url) {
+			if (isString(url)) {
 				data = {
 					releaseNotes: '',
 					version: '',