Yes, I had big time crashes when trying to exit cnfx when I first installed pre2 software.
I narrowed the problem down to the following, but of course your mileage may vary.
If I loaded two clips into cnfx, it pipes one into the bkd and one as an input, if i then added another input and connected that input to the bkd clip it crashed 100% of the time when i tried to exit. However,In the same scenario, if i disconnected the bkd clip from the action node it was fine.
If i repeated the same steps and instead of adding an input and connecting to the bkd clip, if I added the clip directly into the media list no problems, or if I added an input and drag/dropped
the same bkd clip from the media library, no problem.
So, If I need to turn a bkd clip into an input clip I make sure to disconnect it from the action node...I don't think I've had a crash since and I've been pounding cnfx fairly hard on a recent project.