>Over the weekend I installed DOTLESS package into my ASP.NET Web Forms project. And I was testing the application without problems.
>
>But today when I try to run/debug the project (without any major changes) I get the following error:
>
>

>0x800a139e - Microsoft JScript runtime error: ASP.NET Ajax client-side framework failed to load.
>

>
>The error is called by the following code:
>
>

><script src="/bundles/MsAjaxJs?v=J4joXQqg80Lks57qbGfUAfRLic3bXKGafmR6wE4CFtc1" type="text/javascript"></script>
><script type="text/javascript">
>//<![CDATA[
>if (typeof(Sys) === 'undefined') throw new Error('ASP.NET Ajax client-side framework failed to load.');
>//]]>
>

>
>Any suggestions to what causes and how to fix this issue?
>
>UPDATE: some additional information. When I start/debug the project in Chrome, no problem. So the problem is only when I use IE (9.0).

Hmm. Seems to me there are two possible causes:
(a) Browser doesn't find the script at the advertised URL or
(b) The JavaScript test to determine whether it was loaded OK isn't valid (or runs too soon)

Use the debugger in Chrome to check (on the Network tab) whether the script is downloaded OK.
If it is then do the same in IE. If it downloads OK in IE then check when the 'if(typeof(Sys).....) runs.

Oh, and make sure that Chrome doesn't just *appear* to be working because the script has been cached.......