Introduced in Mac OS X 10.7, it remained an HFS+ partition until High Sierra. With Mojave, it became an APFS volume, except for M1 Macs.
recovery
Recovering from one regular panic should be straightforward. But what if it’s a boot loop, in which your Mac tries to start up, panics, restarts, in an endless loop? Don’t panic: here are the solutions.
Installing two different versions of macOS within a single container brings flexibility as they share free space, a little economy maybe, and complexity – explained here.
Are you testing or going to test Monterey beta? Advice on kernel panics, the M1 missing boot disk problem, updates and escape routes.
Terminal in Recovery on an M1 Mac has access to many valuable command tools, including USB-C diagnostics,options otherwise unavailable in csrutil, and more.
Install macOS in Recovery can only install one version, which probably isn’t the one you want. How can you get an earlier version installed, then?
How useful is the traditional panacea of re-installing macOS in Big Sur? And is it worth maintaining an external recovery disk to deal with problems?
Erase your M1’s internal storage in Recovery, reinstall macOS and you could see an error in which it failed ‘to personalize the software update’. That’s not easy to fix, as explained here.
What would happen to a Mac’s firmware if you installed Monterey beta to its internal or external disk? Could that be reversed?
Recovery on an M1 Mac runs from its own container, which should improve its robustness. It has one simple entry point, and offers a full range of facilities in an integrated environment. It’s a big step forward.
The Eclectic Light Company 