Can I erase my internal drive from a bootable external?

[greyeyezz]

2020 iMac, have Ventura on the internal, Monterey on the external. I want to erase the internal, CCC backup to the internal, then run the Monterey installer from my booted Monterey external aimed at the internal. I already have a cloned external of Ventura. Basically flip drives.

I want to do it this way so I don't have to boot to recovery console then run migration assistant.

 

[FreakinEurekan]

Probably? ¯\_(ツ)_/¯

Give it a try!

 

[Fishrrman]

If I recall, the 2020 iMacs are the only ones that have the t2 chip, which could impact things here.

The first thing you should do is to boot to recovery (I would suggest internet recovery instead, "command-OPTION-R" at boot).

Then go to the startup security utility and choose the LOWEST security for everything.

I would also open terminal and disable system integrity protection by entering:
csrutil disable

You might have to reboot to activate the disabling of SIP.

I don't think you can "get around" having to go to recovery FIRST to do the above.
Again, this is because of the t2 chip.

MORE to consider.
Mac OS Monterey has the "sealed system volume".
I'm wondering how this is going to impact things with an Intel CPU.

I know that you COULDN'T do what you want with Apple Silicon.

And again, it used to be EASY to use CCC to do a complete restore (OS & data) BEFORE the t2 and sealed system volume. But now...?? Other users need to jump in with more experience.

If it was me, I'd do this:
1. Create a bootable USB flashdrive with the Montery installer (16gb flashdrive or larger)
2. Do a final CCC backup, then set it aside for the moment
3. Boot from the flashdrive installer
4. ERASE the internal drive to APFS
5. Install a completely fresh copy of Monterey
6. During setup, connect the CCC backup and migrate apps, accounts, data, etc., from that.

Doing it this way ensures that the t2 and sealed system volume won't become issues.
Again, looking for experiences from others...

 

[FreakinEurekan]

If I recall, the 2020 iMacs are the only ones that have the t2 chip

2020 and iMac Pro.

 

[greyeyezz]

If I recall, the 2020 iMacs are the only ones that have the t2 chip, which could impact things here.

The first thing you should do is to boot to recovery (I would suggest internet recovery instead, "command-OPTION-R" at boot).

Then go to the startup security utility and choose the LOWEST security for everything.

I would also open terminal and disable system integrity protection by entering:
csrutil disable

You might have to reboot to activate the disabling of SIP.

I don't think you can "get around" having to go to recovery FIRST to do the above.
Again, this is because of the t2 chip.

MORE to consider.
Mac OS Monterey has the "sealed system volume".
I'm wondering how this is going to impact things with an Intel CPU.

I know that you COULDN'T do what you want with Apple Silicon.

And again, it used to be EASY to use CCC to do a complete restore (OS & data) BEFORE the t2 and sealed system volume. But now...?? Other users need to jump in with more experience.

If it was me, I'd do this:
1. Create a bootable USB flashdrive with the Montery installer (16gb flashdrive or larger)
2. Do a final CCC backup, then set it aside for the moment
3. Boot from the flashdrive installer
4. ERASE the internal drive to APFS
5. Install a completely fresh copy of Monterey
6. During setup, connect the CCC backup and migrate apps, accounts, data, etc., from that.

Doing it this way ensures that the t2 and sealed system volume won't become issues.
Again, looking for experiences from others...

Thanks for the info, steps 1-6 is my normal process. When everything is working fine I'm not happy, I have to muck something up. I love being on the phone with apple tech support, I'm very lonely.🤐

Just leaving everything alone.