title: Microsoft Visual Studio 2019: The project file cannot be opened. Unable to locate the .NET SDK
body: <p>I just upgraded my visual studio <em><strong>2019</strong></em> to latest version <em><strong>16.8.3</strong></em> and suddenly I am not able to load any C# project and getting the following error for all .NET core projects:</p>
  <blockquote>
  <p>The project file cannot be opened. Unable to locate the .NET SDK.
  Check that it is installed and that the version specified in
  global.json (if any) matches the installed version.</p>
  </blockquote>