When using Authentication with a Web Application you might get Sys is undefined when starting up in Visual Studio using IE. This is an Authentication issue that is resolved by using this solution.

 

 

 <location path="Telerik.Web.UI.WebResource.axd">
 <system.web>
 <authorization>
 <allow users="*"/>
 </authorization>
 </system.web>
 </location>

 

Hope this helps someone out there!