title: Xamarin.forms app not building after updating Visual Studio. Could not find file AppName.dll
body: <p>After i updated Visual Studio 2019 Community (ver. 16.4.5) and Xamarin.Forms to latest stable builds, I'm no longer able to build my app. Now when i try to build it, i get 2 identical errors like this:</p>
  
  <pre><code>Severity    Code    Description Project File    Line    Suppression State
  Error       System.IO.FileNotFoundException: Could not find file 'D:\Didakticke testy\Didaktick-testy\DDKTCKE\DDKTCKE\bin\Debug\netstandard2.0\ČJ-Didaktické testy.dll'.
  File name: 'D:\Didakticke testy\Didaktick-testy\DDKTCKE\DDKTCKE\bin\Debug\netstandard2.0\ČJ-Didaktické testy.dll'
     at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
     at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
     at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
     at Xamarin.Android.Tasks.FilterAssemblies.RunTask()
     at Xamarin.Android.Tasks.AndroidTask.Execute()   DDKTCKE.Android     
  </code></pre>
  
  <p>I already tried :</p>
  
  <ul>
  <li>Deleting Obj and Bin folders </li>
  <li>Cleaning solution</li>
  <li>Rebuilding solution</li>
  <li>Killing process msbuild.exe</li>
  </ul>