title: mscorlib version conflict during build
body: <p>On a new Win8.1 reinstall, with all of my code restored from backup, I'm suddenly now getting a Visual Studio warning when I build the main project of my solution:</p>
  
  <blockquote>
    <p>Found conflicts between different versions of the same dependent assembly that could not be resolved.  These reference conflicts are listed in the build log when log verbosity is set to detailed.</p>
  </blockquote>
  
  <p>I set the Output log level to Detailed and I found a few entries like this:</p>
  
  <blockquote>
    <p>There was a conflict between "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" and "mscorlib, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e, Retargetable=Yes". "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" was chosen because it had a higher version.</p>
  </blockquote>
  
  <p>Trouble is, I'm not referencing <code>mscorlib</code> anywhere in the solution—old <em>or</em> new. I have a couple of apps on my machine that require .NET 3.5, but I can't see how that could be related.</p>
  
  <p>One difference: the old Win8.1 install on which this warning did NOT occur was a standalone machine; this time I'm domain-joined. I don't know whether that makes a difference (I can't see how), but I thought I ought to mention it at least.</p>