Photos reinstall process help

[AppleInLVX]

Hoping for a little help. I decided over the holiday to do a clean install of Catalina on my iMac (format drive and install). Everything went smoothly (I think) but the photos. See, I realized afterward that there was a lot of SD hard disk space taken up by photos. I resolved this before the install by having the photos in icloud, with originals kept on a library on an external volume. Great, so I thought that’d be easy. Although photos had already co-opted space on my SSD for the photos, I pointed Photos at the editing library on the external drive, designated it the system library, and hoped all would be well, but its taken a *long* time to index it, and just last night it displayed that it had started the process of uploading all 11,000+ photos to iCloud.

My expectation was that it’d just do a compare with what’s on icloud and carry on. The photos, such as they are, work perfect on iPhone and iPad, but now somehow something isn’t right with the iMac. So, I guess my question is, have I done this right or is there some magic I’ve forgotten to cast here to get an existing local library on an external drive to sync with the iCloud version? They should be only about 20 photos out of sync... I really don’t want duplicates for 11 thousand images in iCloud...

Any thought appreciated.

 

[robgendreau]

I can't tell where the photos were before you started. Photos prioritizes storage in the cloud. You erased the system library. I would have restored the system library from a backup (actually, I wouldn't have erased it in the first place), and then let it try to sync up.

From your description, however, it sounds like you've designated a NEW library as the system library. So that means Photos thinks those are new photos it must upload.

 

[AppleInLVX]

Interesting. I'm not sure I could have avoided it though. I only have a 512G SSD in the iMac, so keeping all the photos on it is a bad idea, as it eats up a nontrivial amount of space. The point was to offload to the external drive which means I need to designate a new location and thus new library and so I just designated what I've been using forever (as that drive didn't get formatted when I did the upgrade). I wonder if I just backed up the library and started fresh if iCloud would then simply download the originals again. Hmm.

Thank you for your thoughts!