Do you have Ensemble or Solo? I've read that if you try to load a performance that includes GigaPulse capabilities only offered in Orchestra, it will crash the lesser two versions without warning.
One example would be the VintAudio C7 performance files. They inlcude GigaPulse setups. I believe that Franky is offering GSI files to Solo and Ensemble users. All versions support stacked instruments (GSIs) with integrated GigaPulse. Only Orchestra supports GigaPulse Pro. It allows you to put GigaPulse in the DSP section and apply any impulse to any instrument.
Then again, if you have Orchestra, it's something completely different!
I have no idea what I could be doing that triggers this. I haven't actually sat down and tried to figure it out either cause I've been in such a creative groove lately.
*thinking out loud*
I don't do anything out of the ordinary (or at least what I think to be out of the ordinary). I do some iMidi stuff with GigaPianoII so I can play the lower notes but that's about as different as I get... Sometimes I unload all unmapped instruments right before saving ...
Dammit! I'm a software tester, I should be able to figure this out! I'll spend a day trying to narrow it down and get back to everybody because I know there are a couple of people here that have had the same problem.