.net - NuGet add reference error while installing packages

Question

I am not able to install any package by Nuget. For example when I want install entity framework I receive following error:

install-package EntityFramework
Successfully installed 'EntityFramework 4.2.0.0'.
Successfully uninstalled 'EntityFramework 4.2.0.0'.
Install failed. Rolling back...
Install-Package : Failed to add reference to 'EntityFramework'.
At line:1 char:16
+ install-package <<<<  EntityFramework
   + CategoryInfo          : NotSpecified: (:) [Install-Package], InvalidOperationException
   +FullyQualifiedErrorId:NuGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand

I receive same error while installing every package from console or gui. Reinstalling nuget, disabling other extentions and running VS as admin did not help me.

Regards

Answer 1

I had this problem too, the fix that worked for me was:

1. Delete all the folders inside of the packages folder.
2. Update all packages in Nuget Package Manager.