photo library on the external hard drive cannot be repaired

thebullers wrote: …When I tried to connect my iCloud to the new Photo Library, it said it couldn’t, because there was another library connected to iCloud.

First, are your external drives formatted in APFS format or Mac OS Extended (Journaled) format? If not, there are no ends of problems. Be sure, before you do things to Libraries, that you have pristine copies!

A Mac can have several Photos Libraries, but only one, the System Library, can be connected to iCloud. Designating a Library as the System Library is done in Photos' Settings>General. If you switch System Libraries, then iCloud will combine whatever is in the new Library with what it already has, doing its best to avoid duplicates.

So, I bought a 4 TB SSD drive. The first thing I tried was to repair the Photo Library on the old 1TB SSD by removing the biggest video files from the package contents.

Removing files pretty much destroys a Photos Library. I hope you're dealing with copies.

My newest plan is to create a new, empty Photo Library on the Mac mini, move it to the 4TB SSD and then download the photos from my iCloud library (all my photos from 2017 forward).

OK. Filling a new Library with 1TB of pictures will take more than a week-- maybe two or more, depending on what else you have the Mac doing.

Then, I will extract all of the jpeg/HEIC files from the originals folder on the old 1TB SSD and import them into the photo library. I am hoping that any duplicates will be eliminated in the process.

Files in "Originals will not have recognizable file names, but they will otherwise by just like the originally loaded files before any edits or comments. Be sure to use Photos' IMPORT command.

I will probably purchase a software to eliminate the duplicates in any case.

Most 3rd Party cleaning or duplicate erasing software will destroy a Photos Library. Photos does a pretty good job on its own. If you insist, then the best is the trusted 3rd party app PowerPhotos ($35,) which is way useful if you have multiple Libraries.

Will I lose the time stamps of the photos this way? IOW, will all photos I transfer from the “originals” folder on the old 1TB SSD drive be considered created on the day I transfer them?

No-- they are originals, so they have the original metadata. If they had the correct creation date before you originally loadied them into Photos, they will still have it.

Are there any other risks associated with extracting the original jpeg/HEIS files from the old 1TB SSD drive?

I don't quite understand what you have at iCloud.com that might be the same or different. If iCloud is the same as the old Library, I'm not sure what adding all those pictures to iCloud is for.

Is there a better way to go about this?

I think if I had a corrupt Library (and I did years before iCloud,) then I would just set an empty Library on a larger properly formatted drive as the System Library and connect it to iCloud and wait for it to fill--like you said. Then I'd look through for missing pictures.

You can load the originals into the new Library and let Photos find duplicates-- but it may take a very long time (month or more) and you will have a mess in the mean time. The difference in the file names will make it harder.

One more thing, Jennifer.

When Photos crashes and is leaving the library in an inconsistent state, it will need plenty of free storage on the disk to be able to repair the library. The amount of free storage needed for repairing seems to depend on the size of the library. The same applies to upgrading a library, when you install a new version of Photos with a system upgrade. It is great that you know have a larger drive, but don't let your library grow much lager than it is now. Keep enough storage free so you could store a duplicate of your library on the same drive as a backup copy, if need by. then the free storage should be sufficient for upgrading or rebuilding the library.

While you are recreating your library anyway, you may want to check, if you can split it into smaller chunks.

It is great to have all photos we may need for some project in the same library, but if the library is huge, Photos will become very slow for tasks, that require to scan the complete library again, for example, after resetting iCloud or repairing or upgrading the library. My strategy is to keep my iCloud Photos Library relatively small, by keeping only the best versions of all photos in iCloud, the photos that I want on all my devices at all times. And I am keeping a local archive of all photos on my external drives, just in case, that I need to check my other photos for some reason. The archive is split into smaller libraries. When I need a photo from the archive, I can quickly open the smaller library for that year.

PowerPhotos is very useful to move photos and videos between libraries. I am regularly exporting partial Photos Libraries from my iCloud Library to the archive.