Was trying to research how to create a bootable backup on a USB-C external drive under macOS Monterey. I am using a backup tool called ChronoSync, so I started to research and found a tech note about bootable backups.

No longer can you just make a copy of your main hard drive and make it bootable. You need to first install macOS on an external hard drive, according to Macworld.

The above article recommends that I format the drive as an macOS Extended format. Is that correct? I thought that we were using APFS now, and my internal drive is formatted as an APFS Volume Group.

I couldn’t test this because when I clicked “Show All Disks…” in the installer to see external drives for installation, the installer told me that I could not install on the volume I had chosen because it was part of an AppleRAID.

AppleRAID volumes do no support installing a bootable drive.
AppleRAID volumes do no support installing a bootable drive.

Looks like I will buy a dedicated backup hard drive and update this. If you have any suggestions on external drives for bootable backups, then tweet me.