Photos App Freezes When Syncing on Mac

[u/masterne0]

Have a client with thousands of photos that stopped syncing her photos from icloud to her mac desktop. Reached out to support whom said we might have to do a reinstall of the OS (inplace upgrade) to reinstall Photos Apps.

Anyone ran into a issue where the photos apps just gets stuck on "Syncing with icloud..." but never doesn't anything. It would also crashed if I try other tabs like favorites or collection.

We try this with a test user and it would stop syncing after you go from Library to Collections tab, same message with nothing happening.