yet another update:
I updated Photo 1.7.0.367 to 1.7.0.380. Update ran successfully. Launched Photo, tried to add a curves adjustment and Photo goes into "not responding" mode. I noted in task manager that even though Photo was "not responding" it was using 27% of cpu and an instance of crashpad_handler.exe was running in the process stack. I let this run for 10 minutes and then killed the process. No diagnostic data found in %appdata%\roaming\affinity\photo\1.0\[attachments | backtrace | reports] .
I'm disappointed that almost a week has passed and, except for an initial "try this", I've received no response/advice on this problem. If I'm using the wrong forum to ask for help, please let me know the correct procedure. Based on what I see in the forum, you guys look rather busy with the roll-out of 1.7
The only good news is that I've learned how to have 1.65 and 1.70 co-exist.