Visual Studio 2012 says website project's project file is edited outside of environment

Question

After installing Visual Studio 2012 and opening/upgrading a Visual Studio 2010 solution from Team Foundation Server that contains two "website"-type projects I keep getting the message that "The project 'website' has been modified outside the environment" with the option to reload every time I add or remove a file to the "website" project.

This is odd, because as far as I know this type of project does not have a project file and thus it is impossible to edit it, in addition, nobody is editing anything outside of the environment.

Does anyone know what causes this and how to fix it?

Answer 1

To at least partially answer my own question. You can solve this by closing Visual Studio 2012 and then deleting the .suo file for the solution. It should be sitting right next to the solution file and has the same name.

After deleting this file I reopened the solution and VS2012 went to get the entire solution from TFS again. When it was done, the problem was gone!