Could be me, but SGP locked up and became unresponsive multiple times (4?) last night under what might be unusual conditions.
I asked SGP to center and rotate (manual rotator) on a target. Because I was having some stiction problems last night, the mount didn’t quite get on target and the centering and plate solve algorithm began searching several hundred sections as it is supposed to do. No problem there. Knowing it would not be able to solve, I “aborted” the solve. And it stopped and left me with the centering pop-up, as expected. I then clicked “done” so it would close and I could try slewing to the target again. But nothing happened. SGP did not formally go “not responding”, but nothing happened. The “Done” button goes gray and the pop-up just sits there. I waited maybe 30-60 seconds but nothing happened. There was no way to exit the popup - no “X” on the pop-up to close the window and with the pop-up open, the main SGP “X” was not active. I had to use task manager to stop SGP. Thinking maybe I was impatient the first time and needed to wait longer for SGP to close the pop-up, I tried again and with the same mount problem of not reaching my target, I went through the same routine but waited longer, but got the same lock up and had to force Windows to shut down SGP. I did this 3 or 4 times. I fixed the mount problem and rest of the night was fine, but I didn’t have that same scenario of wanting to abort the plate solve routine and bail out of the centering pop-up.
I rarely have mount trouble, so this scenario hasn’t come up in several years so I don’t know if it would have happened with any beta before 320.
I have the log file and will try to upload it in a minute.