Strange error when opening a solution in Visual Studio 2010

Question

Gentlemen I have a solution which contains 2 MVC projects. When I open the solution I get the following error: Never had this error before. I'm developing in Visual Studio 2010.

Muralidharan Deenathayalan · Answer

Are you opening the MVC applications from IIS ? Make sure ASP.net version 4 is registered in IIS.

Olivier Muhring · Answer

As it turns out a colleague om my made some changes to the project requiring a working & configured installation of IIS. Since IIS wasn't installed on my machine I needed to install it and then run the aspnet_regiis -i command. like this: After this the error dissappeared.