Restore mac Mini with a semi-recent backup

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Level 1

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Restore mac Mini with a semi-recent backup

I upgraded my very old mac Mini to Catalina, which is the most recent macOS supported for the device. I now wish to restore to a point in time a couple of months ago just before I upgraded from Sierra (10.12) to Catalina (10.15).

When I boot into recover mode (⌘R), I can recover only using backups taken after the upgrade to Catalina. When I try to restore using the latest backup for Sierra, it complains saying...

The system can't be restored onto this disk because HFS systems can't be restored to space sharing APFS volumes. Reinstall macOS on this disk and then use Migration Assistant to transfer data from your backup instead.

When I use Disk Utility, I see that the Macintosh HD filesystem type is APFS (expected). I guess when I upgraded to Catalina, the filesystem type was changed from HFS to APFS.

Do I really have to reinstall Catalina (but use HFS for the filesystem type) or can I use Disk Utility to reformat the hard drive using HFS?

After all, I don't think I care what's on the hard drive right now. And, frankly, I don't recall if I can choose the filesystem type (APFS might be forced). But that's why I'm asking now rather than later after I supposedly would make yet another mistake.

Posted on Aug 23, 2023 11:45 AM

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Answer 1

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woodmeister50

Level 6

19,831 points

Aug 24, 2023 6:17 AM in response to method-r.com

Catalina will only operate with the APFS file system.

Rolling back to pre-APFS, would be a bit of work. First and foremost, you would need to back up all your user data to an external drive. Next, you would need to create a Sierra USB installer. Then, boot from the installer and open Disk Utility on it. Then erase the internal drive, not just the volume containing MacOS, with GUID partition and MacOS Extended (journaled). Then proceed to install Sierra and when complete, install your apps, then start migrating your data back from the external drive.

You may be able to restore your apps and data from a recent Time Machine backup but I have never done that jumping that far back plus I believe that Catalina may alter the Time Machine backup to APFS which Sierra cannot recognize. I am not positive about this and some else can correct me if I am mistake.

See how to get MacOS Sierra:

How to download and install macOS - Apple Support

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Answer 2

method-r.com Author

Level 1

4 points

Aug 23, 2023 2:07 PM in response to WheelieNick

True, and I wasn't clear about my fear, but will reformatting the drive prevent me from restoring from one of the backups in the list of backups. In other words, will reformatting the drive prevent the restore software from showing me the list of backups on the backup device?

Sorry if I seem paranoid but you can understand my fear when I say it's odd that the restore software won't ask me if I want it to reformat the drive. I would have thought that would be a capability of any restore software. The fact that it's not there makes me wary.

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Answer 3

method-r.com Author

Level 1

4 points

Aug 24, 2023 6:18 AM in response to woodmeister50

Catalina requiring APFS is what I vaguely recalled and so that's why I didn't believe reinstalling Catalina would be an answer.

But what I want is simply restore from the backup when Sierra was installed using HFS. @woodmeister50, are you certain I can't simply reformat the drive with HFS and then restore from that aforementioned backup?

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Answer 4

Aug 25, 2023 5:36 AM in response to method-r.com

If you do a "complete system" restore from a Time Machine backup, it will be what ever the last OS that was on the machine at the last backup. You can't erase a drive and tell Time Machine to restore a "complete system" to such and such date in the past. Now, if the last backup was a Sierra backup, then you may be able to restore to Sierra. If it was Catalina, Catalina will be what you get. In either case, you end up with a machine at whatever state the machine was in at the time of the last backup.

Even during a clean install, when migrating a Time Machine Backup, you can chose a few areas such as users, apps, settings, etc. but you cannot chose a specific date in the past.

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Answer 5

method-r.com Author

Level 1

4 points

Aug 25, 2023 6:09 AM in response to woodmeister50

Sorry to be a pest but the first thing the restore does is erase the disk. If it erases the disk, then it has to obtain the OS from some place. Surely that place is some backup, either the one you chose or an earlier one where the OS was backed up, right?

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Answer 6

WheelieNick

Level 8

38,171 points

Aug 23, 2023 1:07 PM in response to method-r.com

When reformating the drive, you can choose the file system type.

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Restore mac Mini with a semi-recent backup

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