Why does Visual Studio create a new .vsmdi file?

Question

If I open a solution in Visual Studio 2008 and run a unit test then VS creates a new .vsmdi file in the Solution Items folder and gives it the next number available e.g. My Solu

Answer 1

It appears that the VSMDI problem is a known bug and has been around since VS2005 Team System but it has no clear fix as yet. Another reason to NOT use MS Test.

An MSDN blog details how to run unit tests without VSMDI files.