title: Unable to load assembly. Ensure that the file is a valid .Net Framework assembly
body: <p>I have an issue in Microsoft Visual Studio 2008 developing a Smart Device Solution with .NET CF 3.5.</p>
  
  <p>The main project is Smart Device Application Project (normal executable for smart devices - WinCE).</p>
  
  <p>This project is referenced to Microsoft.WindowsCE.Forms assembly <a href="http://i.imgur.com/3Ej9eAp.png" rel="nofollow">as follows</a>.</p>
  
  <p>Now, if I try to <a href="http://i.imgur.com/tw1K8Km.png" rel="nofollow">add a new item to the application project and choose the item to be an inherited form </a>, VS pops up an error that the assembly  <a href="http://i.imgur.com/UJqr50T.png" rel="nofollow">is not a valid .NET project</a>.</p>
  
  <p>But dialog with all forms in main project is still shown.</p>
  
  <p>This EXE is also SDAP executable (WinCE device). But this EXE has never been referenced to and more - it is exluded from Build all process. </p>
  
  <p>This warning/error message has been never shown before.</p>
  
  <p>What options should I check to solve this problem? </p>