I will try to isolate the issue but past experience told me it took a lot of time systematically stripping away code to the minimum that still repro'd the problem.
What does removing this registry key do? How does it help me? Will it stop RobotC from crashing? Or will it just stop loading the previous project and auto compiling it that caused the crash?

Thanks.

quick reply; I found a bug in my code earlier where I was printf'ng 2 floats, and accidently passed in an int for one, locked the brick up, found it quickly, couldn't reproduce though.

Yes, it'll remove the "last startup project" so ROBOTC will at least start... it won't fix the issue of the crashing.

We can isolate the issue in your program if you want to e-mail your files (don't forget any includes) to tfriez [at] robotc (dot) net