Error building empty website in VS2012

Question

I am using Visual Studio 2012 Update 3 and whenever I create a new ASP.NET empty website and build it for the first time compilation is successful but I get a server error when accessing the site of "Could not load file or assembly 'System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The module was expected to contain an assembly manifest."

If I then go back and build the website again I get a single error of "Object reference not set to an instance of an object" but no line number.

This error occurs whichever framework I am targeting and whether I am using C# or VB.

Can anyone point me in the right direction please?

Thanks, Richard.

Answer 1

Possibly AjaxControl Toolkit is the issue.

Depending on your Framework version( 4.5, 4.0, 3.5 ),, install the correct version of AjaxControl Toolkit from here: http://ajaxcontroltoolkit.codeplex.com/releases/view/94873 .

Another solution I found is to place System.Web.Extensions.dll and System.Web.Extensions.Design.dll directly in the Bin folder of your web application.