NuGet Package restore failed for project Miscellaneous Files: Value cannot be null or an empty string. Parameter name: root. 0 0

Question

I have such error in vs 2012: NuGet Package restore failed for project Miscellaneous Files: Value cannot be null or an empty string. Parameter name: root. 0 0

I see

Answer 1

A simple restart of Visual Studio should clear everything up. I had the same issue in VS2013 after upgrading Web API. It was not necessary to delete the .suo.