Any way to share a Photos library between Mojave and High Sierra Macs?

[ScottR]

I have a Photos library on an external drive (both the photos and the .photoslibrary file). It contains scans of photos ranging from 40-60 years old. I'd been ID'ing the people in it with the help of my mother (who's 89) and to to do so I'd set up one of my old Macs for her (well, really for me, since she doesn't use computers). This worked fine for a long while until I "upgraded" my own Mac to Mojave--something I'd put off after a disastrous upgrade attempt early this year but finally went ahead again with back in September. The computer I'd set aside for her, a mid-2010 iMac, cannot run Mojave.

Of course, when I opened the library in my newer iMac it updated the library to v4, so I can't now read it on the old computer.

Aside from downgrading my own Mac to High Sierra (something I'm considering, but for the headache, since I'm less than thrilled with Mojave) is there any way to share the library with the two Macs? The only "solution" I've been seeing is iCloud photo sharing, which is neither something I want or practical under the circumstances. Or would this require some third-party photo database that can also handle identifying faces? (if the latter, I'd want an OS X application, not the cloud.)

The files and database are backed up so I haven't lost anything, but I'd like to be able to go back and forth. And since I have all those people ID's in Photos I'd love to be able to access that information on both.

 

[Fishrrman]

Such are the problems of trying to run one (older) version of Photos "against" a newer version of the library.

I'm not well-versed enough in Photos to absolutely know if there's a "workaround" -- but I sense that there isn't.

What's the solution?
Get your mom a Mac that runs Mojave.
Then there will be no "old version - new version" conflicts.

Even putting YOUR Mac back to High Sierra may not work, because then NEITHER Mac will be able to work with the "updated" library...

I could be wrong.

 

[ScottR]

Such are the problems of trying to run one (older) version of Photos "against" a newer version of the library.

I'm not well-versed enough in Photos to absolutely know if there's a "workaround" -- but I sense that there isn't.

What's the solution?
Get your mom a Mac that runs Mojave.
Then there will be no "old version - new version" conflicts.

Even putting YOUR Mac back to High Sierra may not work, because then NEITHER Mac will be able to work with the "updated" library...

I could be wrong.

So... buy a new[er] computer for the sporadic occasion I need to ID some faces in old photos?

 

[Fishrrman]

How many photos are there?
I'm wondering if you could "export them" as jpgs from Photos (on the Mojave Mac) to a folder, then re-import them into the older Photos on High Sierra?

 

[ScottR]

As I said I do have a backup so I still have the High Sierra Photos library, but all of those ID'd pictures are "stuck" on that system. The issue isn't recovering the files, it's how can I keep working on ID'ing the photos as I scan and sort them.

If I want to keep on identifying additional photos, the only thing I can think of is to start a new High Sierra .photoslibrary each time and import that library into a main Mojave .photoslibrary, keeping a duplicate High Sierra version of the .photoslibrary. I can then keep combining the new libraries as they're created, as here.

 

[Brian33]

f I want to keep on identifying additional photos, the only thing I can think of is to start a new High Sierra .photoslibrary each time and import that library into a main Mojave .photoslibrary, keeping a duplicate High Sierra version of the .photoslibrary. I can then keep combining the new libraries as they're created, as here.

The link describes exporting the photos from one library and then importing them into another.
Be careful if you go with this approach -- I strongly suspect that exported photos will not include face ID metadata. Probably not keywords, etc. either. Do some testing first!