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I just upgraded to macOS Catalina and that was a pretty bad experience.

I didn't know 32bit anymore, so none of my games work.

Is there a process to back-up everything to prepare downgrading to Mojave or High Sierra.

I'd want to prepare for everything as it was before such as my saved games, existing apps. My supplies are time and an external HD.

Is there a step-by-step guide to perform this?

bmike
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Diego LaCrête
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  • You say you have a backup of your system running Mojave? – Case39 Jun 11 '20 at 00:42
  • unfortunately no. First backup I have is under Catalina – Diego LaCrête Jun 11 '20 at 10:05
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    Then your only solution is 'the hard way' - picking bits out of the backup piecemeal. Things like Mail or iTunes might not be possible at all, as the structure changes. – Tetsujin Jun 11 '20 at 15:17
  • This is exactly what the time machine backup was for. – Thorbjørn Ravn Andersen Jun 11 '20 at 21:11
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    @ThorbjørnRavnAndersen - Time Machine will not go 'downhill'. You'd need a backup from before the upgrade to be able to restore it in one simple step. – Tetsujin Jun 12 '20 at 16:33
  • @tetsu yes. Backups cannot be done after the fact. – Thorbjørn Ravn Andersen Jun 12 '20 at 16:47
  • @ThorbjørnRavnAndersen - that's not what I said. if you don't fully disconnect the backup right before you upgrade, you lose the chance to go back to the old OS. Time Machine will simply refuse to do it. It won't migrate, it won't restore. You're stuck. It catches any people out - you think you're safe because your TM goes back a year. Unfortunately it won't. – Tetsujin Jun 12 '20 at 16:52
  • @Tetsujin I have not tried recently. I understand that the latest time machine backups are locked to the version producing them, but does that apply to those taken before that as well? Is it not possible to restore an old backup taken from say 10.14 to a fresh reinstall of 10.14? – Thorbjørn Ravn Andersen Jun 16 '20 at 13:14
  • @ThorbjørnRavnAndersen - See https://apple.stackexchange.com/questions/271104/revert-to-el-capitan for some thorough testing. Time Machine will simply not go 'downhill'. You can pick bits out by hand, but you cannot restore or migrate to an older OS. Unless you remove the drive before you upgrade, you're well & truly stuck. – Tetsujin Jun 16 '20 at 13:23

1 Answers1

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Copy all important files to another HD (apps, games, your user's library folder, all your other user folders, etc).

Download Mojave, create a USB, boot, erase and install.

Set up the new computer, then copy stuff over. Some things (like Mail, iCloud, some settings, and iTunes data won't work). If you use steam, it should be pretty easy to copy its folder (within ~/Library/Application Support/Steam to your new user.

At0micMutex
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