I have been struggling with this issue since I got my M1 MBP. Now I know why. BST was one of the first utilities I installed that I never used before. After I disabling it, I can once again sync Photos with my iPhone.
Let me know what you need from me to replicate this bug.
Device information:
This must be some weird coincidence. BetterSnapTool can not influence the photo synchronization.
I know it sounds weird but Apple support suggested I start in safe mode to see if Photos worked correctly and it did, so I just began to disable possible culprits and voilà!
Just did it again syncing one picture with BetterSnapTool off and, now with BST activated, Photos hangs as the attached screenshot shows.
Very weird.
It could be a bug in the windowing implementation of the photos app, in that case disabling BetterSnapTool just for that app should also do the trick (by clicking the menubar icon => disable for current application, while Photos is active)
OK, thanks for the tip.
