title: MSB3258: mscorlib 4.0.0.0 and 2.0.0.0
body: <p>So I'm trying to compile a project on VS 2017, and I'm getting this:</p>
  
  <pre><code> warning MSB3258: The primary reference "someLib.dll" could not be resolved because it has an indirect dependency on the .NET Framework assembly "mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" which has a higher version "4.0.0.0" than the version "2.0.0.0" in the current target framework.
  </code></pre>
  
  <p>After that, I have errors relating to this dll (for example, a type or namespace not being in the namespace), but when I double click the error it disappears, along with the red squiggly line in the code, hinting at the fact that it's not the actual problem.</p>
  
  <p>Nothing I tried is working: all of the projects are on 3.5, I removed and re-added all of my references, and it doesn't happen in any other computer except my own.  I also tried removing mscorlib from the GAC (however dumb that may be), but of course it won't let me.</p>
  
  <p>I saw something that may be relevant:
  <a href="https://developercommunity.visualstudio.com/content/problem/230636/assemblydependency-now-misidentifying-indirect-dep.html" rel="nofollow noreferrer">https://developercommunity.visualstudio.com/content/problem/230636/assemblydependency-now-misidentifying-indirect-dep.html</a></p>
  
  <p>Other than removing and reinstalling VS, not sure what to do.
  If anyone has any idea, I'd be glad to try it.</p>