Duplicate, confusing Photos libraries and....

So eBay Photos.migrated..... is an old iPhoto library that has been converted for the Photos app - into eBay Photos.photos library.

Check that the photos version holds what you need, and the one with migrated in the name can be safely deleted.

I can't say why you have two Merged....photoslibraries. Perhaps you have unsuccessfully tried to convert the iphoto (photolibrary) version twice.

Which library are you opening as your "normal" library?

You will need to open each of the 2 Merged......photoslibrary to see which has the pictures you need.

(To open a particular library, hold down the option key while starting photos. The resulting pane will list all of your libraries and select one to open. It will also tell you which is currently set as your system library...

lymanfrommo wrote:

... I have parked the others in a folder on iCloud rather than delete them just to be safe. ...

iCloud Drive is not a save place to park Photos Libraries, The syncing may corrupt the libraries, because the internal links will not sync properly. You need to keep copies in local drives. Apple says so in "Move your Photos library to save space on your Mac - Apple Support":

"You can't store your library on a storage device used for Time Machine backups. And to avoid possible data loss, don't store your library on a removable storage device like an SD card or USB flash drive, or on a device shared over your network or the internet, including over a cloud-based storage service."

This is like a chameleon, as we can watch on the wayback machine. Initially, in 2014, it pointed to a document named "iPhoto: Sharing libraries among multiple users":

https://web.archive.org/web/20150205073232/http://support.apple.com/en-us/ht201517

Then, in 2017, it pointed to "Sharing photo libraries among multiple users" https://web.archive.org/web/20180103042536/https://support.apple.com/en-us/HT201517

Now it is linking to "Move your Photos library to save space on your Mac" and no more mention at all about "Sharing" libraries, but the text warning about unsafe storage keeps changing. on January 28, 2019 it read "To prevent data loss, Apple doesn't recommend storing photo libraries on external storage devices like SD cards and USB flash drives, or drives that are shared on a network." https://web.archive.org/web/20200313204940/https://support.apple.com/en-us/HT201517

When you migrate from iPhoto to Photos the library format is updated for the new app. The old library is left in place. That is the difference between the photolibrary extension, and the photoslibrary extension.

Normally the old iPhoto library will have the name chagned to add the word "migrated" so that you know it has been updated/copied to a photos library.

It might help if you can post a screenshot of your pictures folder so we get a better idea of exactly what you are seeing.

As a tip - if you decide you need to move/copy photos from one library to another, there is an app called powerphotos (by fat cat software) that will do that for you.

It is paid (Around $£30, but much better than the alternative, which consists of exporting from one library, and importing to the other.

If you wait for the next system version macOS 12 Monterey, you will be able to merge the two libraries fro free. You will be able to import albums and folders directly from one library into the other. It will be the first version of Photos supporting this feature. As you wrote it is not urgent, just keep the duplicate library save, until the release of Monterey.

I was assuming the 2012 imac can't get Monterey.

You're welcome. Thanks for the follow up.