High Sierra ran iPhoto; Catalina runs Photos. The two photo database formats are totally incompatible, which is why it upgrades the database. And I know that somewhere along the way (from HS to Catalina) it did a forced upgrade of the mailboxes.
So my guess is that your undertaking would be an exercise in futility... (And ditto your frustration with the iMac's gossamer-thin screen connection wires: What were they thinking?) -Carl > On Jul 1, 2021, at 3:51 PM, Macs R We <macs...@macsrwe.com> wrote: > > I have a client running Catalina on an old 2013 iMac with a spinner. There's > no reason he needs to be running Catalina (he still uses Lotus 123, for > heaven's sake), he is apparently just a low-information victim of Apple's > antisocial robo-nag campaign to "Upgrade! Upgrade!! Upgrade!!!" > > His machine is now crawling. > > My preference would be to clone his machine to an external, wiping it, > install fresh High Sierra, and then migrate his files back in. But I'm > unsure whether there have been format changes between HS and Catalina in > personal databases such as Photos, Address Book, mailboxes, and the like that > would queer this… or whether File Migration might just arbitrarily nix the > importation out of principle. Not to mention knowing that the System Settings > category (WiFi networks, Apple IDs, Sharing, Accessibility, etc.) would > probably be un-migratable in toto, but that's less important as it can be > addressed manually. > > Can anyone say if this reverse-migration is doomed before it's tried? > > The alternative would be to swap out his HDD with an SSD and clone it over, > which would be a more costly job in terms of hardware fiddlery time (I hate > working on iMacs, having to disconnect all the fragile display screen > connectors to do the simplest things), pus the cost of a new TB drive. > > (Damn Apple's irresponsible pressure on typical consumers to upgrade their > OSes.) > > -- > Macs R We -- Personal Macintosh Service and Support > in the Wickenburg and far Northwest Valley Areas. > http://macsrwe.com <http://macsrwe.com/> > _______________________________________________ > MacOSX-talk mailing list > MacOSX-talk@omnigroup.com > https://www.omnigroup.com/mailman/listinfo/macosx-talk
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