title: Visual Studio 2012 The project file "" has been renamed or is no longer in the solution
body: <p>I recently upgraded my IDE, but not my compiler from VS2010 to VS2012 and now I'm having issues with one of my solutions. When I try to build it I get below message.</p>
  
  <blockquote>
    <p>The project file has been renamed or is no longer in the solution </p>
  </blockquote>
  
  <p>And when I try to build the individual projects I get below message </p>
  
  <blockquote>
    <p>A build is already in progress</p>
  </blockquote>
  
  <p>I've tried removing and re-adding all the projects, but that doesn't help. I even created a brand new solution with all the same projects, but when I tried to build I got the same errors as with the original solution. </p>
  
  <p>I've read that lot of people have similar problems to this, but none of their solutions have helped me so far.</p>
  
  <p>One suggestion was to see if any projects had any missing reference but I'm not entirely sure how to go about doing that.</p>
  
  <p>I tried removing the references and re-adding them but every time I tried to re-add them I got the same error "The project file '' has been renamed or is no longer in the solution"</p>
  
  <p>Any help or suggestions would be awesome! </p>