title: The type or namespace 'Mvc' does not exist in the namespace 'System.Web'
body: <p>I recently installed VS.NET 2012 and moved my ASP.NET MVC 4 project over. However, on building the solution I get hundreds of errors with :</p>
  
  <pre><code>The type or namespace 'Mvc' does not exist in the namespace 'System.Web' (are you missing an assembly reference)
  </code></pre>
  
  <p>AFAIK ASP.NET MVC 4 is built into VS 2012 and there is nothing that needs to be installed. Any ideas how to get rid of these errors and build the application?</p>