MGADiag is almost purely diagnostic - and has NEVER caused any problems that I'm aware of - and I've read over 25000 reports.
It does however uncover pre-existing problems, and makes available information which allows some of us to diagnose problems and also to spot counterfeits. As such, the hackers hate it almost as much as they hate Activation, and will ascribe random errors to it which are in fact nothing to do with it.

I am not a BSOD specialist, merely an Activation and WU specialist, so I'll leave BSOD's to the experts.