Visual Studio 2010 doesn't detect .NET 4

Question

I had a machine all setup with VS2010 & a .Net 4 project. I needed to install and use MSMQ but something with .Net 4 was making it impossible to install. So .Net 4 had to be removed. Now i'm trying to work on the original project but VS doesn't detect .Net 4 even though it was reinstalled. Also, IIS doesn't detect it either. I get the 'This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.' error.

The .Net verification utility says both client and extended are installed properly. I tried uninstalling/reinstalling .Net 4 and I looked at the recommended registry keys for detection and everything is there as expeceted.

I have seen one person say that they could only resolve it by starting the mahcine over. I can't do that. Any ideas on how to fix this?

Answer 1

Uninstalling .Net 4 without uninstalling Visual Studio 2010 is likely the source of your problem. Visual Studio 2010 has a fundamental requirement on .Net 4 being installed and simply won't run without it. I'm very surprised you were able to do this at all.

The next step I would take is to attempt to repair the Visual Studio 2010 install. This is your best bet for getting things up and running again.

• Go to the "Add / Remove Programs" menu
• Select Visual Studio 2010
• Choose Repair