Yesterday, when I was trying to run my copy of 3ds max and Maya, I was suddenly presented with the following cryptic exception message:

An application has made an attempt to load the C runtime library incorrectly. Please contact the application's support team for more information.

Wait, what the hell? So obviously I assumed it had something to do with the way I had recently changed some stuff I was working on, whether it was to do with win32 COM or screwing around with python subprocesses. After spending two hours getting nowhere re-installing MFC redistributables and .NET runtimes and finding not much information on this particular error, turns out it was due to Mercurial, of all things.

This error can possibly occur when you have an application that adds a incorrectly-compiled version of msvcr90.dll to the system PATH...which in this case was Mercurial. Removed it from PATH, and all was well.