Installing older OS on Partitioned SSD

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Alan Jones3 Author

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Installing older OS on Partitioned SSD

Apparently I'm having a brain fart..., or getting old...,

I have a mac pro that I just installed a new 1TB SSD into.

I've partitioned it half, with one side running the most recent Big Sur 11.6

I've formatted the other side, but want to load OS Mojave 10.14 to it.

My objective:

I have an imac thats on it's backend running 10.14.5

I want to transfer all that systems OS to the empty formatted partitioned drive.

The internal HD is dead, and I'm operating it with an external SSD that is removable from it's external set up.

i.e. , 10.14.5 can travel to another external drive if need be.

I do have an external drive set up on my mac pro.

What is the easiest way to accomplish this?

I've tried migration assistant, Cmd opt. R, ect, but have failed to be able to load the Mojave installer, or transfer the 10.14.5 info to the empty partitioned drive.

Any thoughts appreciated.

Thanks, AJ

Mac Pro

Posted on Sep 30, 2021 9:55 PM

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Answer 1

Sep 30, 2021 10:13 PM in response to Alan Jones3

If you have a working Mojave install, use Carbon Copy Cloner to clone it to the same APFS volume container as Big Sur (not necessary but that saves space on the SSD). CCC support recommends using an older Mojave certified version of CCC but a current version might also be OK if that is difficult in practice (i.e. you should boot into Mojave to clone it elsewhere).

Or download full Mojave installer and install a small Mojave system with the desired old apps to such APFS volume (saves even more space as old cruft is not carried over).

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