title: WebDev.WebServer40.exe has stopped working - File not found
body: <p>If I try to run my asp.net mvc web app in Visual Studio Debugger (by pressing F5) I now get this error:</p>
  <blockquote>
  <p>WebDev.WebServer40.exe has stopped working</p>
  <p>Additional details:</p>
  <p>Problem signature:
  Problem Event Name:CLR20r3<br />
  Problem Signature 01:webdev.webserver40.exe<br />
  Problem Signature 02:11.0.50727.1<br />
  Problem Signature 03:5011ca7e<br />
  Problem Signature 04:WebDev.WebServer40<br />
  Problem Signature 05:11.0.50727.1<br />
  Problem Signature 06:5011ca7e<br />
  Problem Signature 07:88<br />
  Problem Signature 08:19e<br />
  Problem Signature 09:System.IO.FileNotFoundException<br />
  OS Version:6.1.7601.2.1.0.256.1<br />
  Locale ID:2057<br />
  Additional Information 1:0a9e<br />
  Additional Information 2:0a9e372d3b4ad19135b953a78882e789<br />
  Additional Information 3:0a9e<br />
  Additional Information 4:0a9e372d3b4ad19135b953a78882e789</p>
  </blockquote>
  <p>If I choose the option to &quot;Debug the program&quot;, it opens up in VS with the following error:</p>
  <blockquote>
  <p>Could not load file or assembly 'System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.</p>
  </blockquote>
  <p>It was working / deugging fine! I haven't changed anything that I know about</p>
  <p>I've cleared out the asp.net temp files etc... and even installed the VS 2012 update, but nothing seems to be working</p>