I’m setting my new MacBook from scratch. I typically have no trouble with this except for migrating my photos library. Almost every time I’ve copied
Photos Library.photoslibrary to a new machine I get Photos.app uploading every photo to iCloud to validate it. My library is 100gb+ so this takes forever. Once a couple years ago I copied the library to a new machine and Photos.app was immediately happy - no validation uploads at all!
I don’t know what I did right in the case when my whole library didn’t need to get validated with iCloud. Any hints on how to get that to happen again?