M1 Macs are not like Intel macs, Apple have done a dismal job of documenting them, and their "for users" tooling is still buggy and broken because the launch wa

M1 Macs are not like Intel macs, Apple have done a dismal job of documenting them, and their "for users" tooling is still buggy and broken because the launch was clearly rushed. Here is what you need to know to actually understand these things: The SSD has 3 partitions. Each partition is an APFS container. Each container contains multiple APFS volumes. Your OS, and everything you care about, is on the second partition/container. The first partition contains boot configurations. The third partition contains the One True Recovery OS (1TR), which includes the Boot Picker menu (that thing you get when you hold down the power button). These partitions form part of system firmware, think of them as part of UEFI/BIOS. Do not touch these. If you mess up those volumes, the only way to recover the machine is via Apple Configurator 2 from another Mac (DFU mode). Disk Utility, the GUI, is broken sometimes. If something doesn't work properly there, ditch it and use the command line. Both Disk Utility, the GUI, and diskutil, the CLI, will hide the first and last APFS containers from you to stop you from shooting yourself in the foot. They're still there, just hidden from the main listing. You can get info for them. Be careful with that. To do OS reinstalls, you want to be in 1TR. This is not the macOS recovery. Hold down the power button and pick Startup Options from there. Then you can use diskutil (preferably the command line version). You should delete the whole APFS container (disk0s2 usually) corresponding to your install, which will contain multiple volumes. Re-create it as APFS. That will create a container with one volume. You can then install to it and the macOS installer will create all the other volumes. Additionally, the SEP data is stored separately from the OS (in one of the volumes of the first container). To wipe that, after wiping the partition and before reinstalling, run `xartutil --erase-all`. I've never tried that myself, and I suspect it's not really required because a reinstall should start with a fresh store, but it's probably a good idea to try if you have authentication/user-related issues after reinstalling. There is also OS recovery, which is the recovery instance that comes with an OS install. It looks exactly the same as 1TR, but it's not the same, and this is highly confusing. For any serious digging around, you want to be in 1TR. Booting holding down the power button will get you there, usually; after a failed macOS boot I've seen it go into regular recovery anyway. To be absolutely sure, boot into 1TR (holding down power, then startup options), then do a clean shutdown, and boot again the same way. More info on what's on the SSD of these things: https://github.com/AsahiLinux/docs/wiki/SW:Storage https://github.com/AsahiLinux/docs/wiki/SW:Storage