Hi, I just started a trial of PI a few days ago and seem to have run straight into a bug. The following information should allow you to reproduce this bug.
Test system: MacBookProRetina 2.6GHz 4-core i7, 16GB ram, I doubt this matters - the system was not under memory or cpu pressure
To reproduce the bug: (I have the steps close, but not exact, you may need to try these steps in different orders, but I have always been able to freeze PI within a minute or two using these steps)
1) load 2 master dark images (I can send you mine if it should matter, but I doubt it and I doubt the image content matters, I just happened to be using master darks from a QHY23)
2) STF them
3)use PixMath to create a new image that is one minus the other
4) STF new image
5) use image statistics with unclipped option (this seems to be key) and click around on the images
6) rerun the PixMath
7) freeze -- oops