title: Visual Studio - Fixing the error "A file of that name is already open"
body: <p>Occasionally (usually after having updated my .sln file in source control) I get a strange Visual Studio error wherein I'm unable to open some of my files. The files in question show up in the appropriate project, but trying to open them results in an error dialog saying "A file of that name is already open."</p>
  
  <p>This is virtually identical to <a href="https://stackoverflow.com/questions/923235/visual-studio-project-with-that-name-already-opened-in-the-solution">Why does it say &quot;Project with that name already opened in the solution&quot;?</a>, except for files, not projects. The solution given there was does not fix this.</p>