title: Nuget package sources not being saved
body: <p>My NuGet package manager cannot save new or find existing package sources.</p>
  
  <p>The location where the package sources are saved %appdata%\NuGet\nuget.config is not getting updated since the problem started. Deleting it does not re-create it when I try adding a new package source through the Visual Studio -> Package Manager Sources dialog.</p>
  
  <p>"Package Manager sources" dialog always shows empty on trying to save something and re-opening the dialog. </p>
  
  <p>This problem started on my laptop after changing my corporate password from my office desktop computer (which does not have this issue).</p>
  
  <p>Re-installing "Nuget Package Manager" did not help. Re-installing Visual Studio did not help. </p>