title: Why is Intellisense not working for one unit test project?
body: <p>I have a Visual Studio 2008 solution which builds a C# class library (Project X) and C# Windows Application (Project Y). </p>
  
  <p>In the unit test project for the C# class library (XTEST) , Intellisense works as expected and auto-completes the names of classes etc.</p>
  
  <p>In the unit test project for the windows application (YTEST), Intellisense has stopped working and only auto-completes with the names of accessor classes, not the names of actual classes. Intellisense also reports lots of class names as being unknown/undefined. These appear in the error tab, but disappear after compilation.</p>
  
  <p>Possibly relevant facts:</p>
  
  <ul>
  <li>The projects all build correctly, and the tests run.</li>
  <li>All programming is in C#, .Net 2.0 Framework, VS 2008 SP1.</li>
  <li>It used to work...!</li>
  <li>The Project Y was converted to VS 2010, then converted back to V20008 at one point. It's possible that other projects may have been converted and then converted back too.</li>
  </ul>
  
  <p>Can any inspired reader point me in the right direction to fix the Intellisense in Project YTEST?</p>
  
  <p><strong>Answer</strong></p>
  
  <p>Turned out to be an issue with .cache files in the project obj directory. Deleting these fixed the problem. </p>