The version of clr.dll does not match the one mscordacwks.dll was built for

Question

I have a C# console app in Visual Studio 2010 that I can run just fine. When I attempt to run the process in debug mode, I am presented with the following error:

Answer 1

I had this when I installed .NET 4.6 for Visual Studio 2013.

In this particular case, restarting Visual Studio 2013 solved the problem.