[reaperman]

Apple Silicon MacBook's are actually a bit difficult to truly factory reset. In a divorce I ended up with an M1 MBP that was first set up using my ex-wife's AppleID, but was primarily my laptop. Her administrator account was deleted, my AppleID was shown in all the system setting menus that I could see in the operating system, and "FindMy" on her phone at least was not tracking its location.

Two years later I updated my login password and then promptly forgot the exact punctuation of the new password. I ended up getting completely locked out of the laptop with no self-service options to fix anything.

That day I learned that you have to boot into a special mode to truly factory reset, not just delete the administrator accounts with other AppleIDs. I was able to get Apple to remotely unlock the computer for me, but only because I could "prove" it was mine by sending them the original invoice slip from store.apple.com with my name, email, and the serial number of the laptop on it.

But that invoice slip is literally a piece of paper in a box, and you can't access it yourself after 18 months - I had to call into Apple support and get them to email me a new copy because it had been longer than 18 months.

If I had purchased the laptop from someone else on craigslist 2 years prior and then got locked out, I would be completely shit-out-of-luck, because I wouldn't be able to prove I truly owned it.

[wtallis]

I think the key thing to check is that the device is no longer shown on the previous owner's iCloud account when checking through the website. It's Apple's servers that you have to ensure no longer hold any association between that machine and an iCloud account that you don't have the credentials for, because the activation lock that survives a complete erase of the machine is implemented server-side.

[tgma]

That is an iCloud lock thing that you need to worry about, but aside from antitheft issue, it’s actually quite nice to reinstall the OS on an Apple Silicon Mac because it behaves like an iOS device. You can simply use Apple Configurator or an open source tool on Linux to DFU restore the device. It’s faster than installing OS by booting into recovery mode.

[philistine]

Even easier than that; Macs now have a restore to factory settings workflow.

https://support.apple.com/en-us/102664

With the way modern macOS is immutable and exactly the same on all machines thanks to signed and sealed images, no one needs to DFU to reset a Mac unless there is something very wrong.

[tgma]

Macs have had internet recovery even in Intel days (command+option+R). On Apple silicon they also have a nice erase process which quickly erases (effacable storage) as you describe but doesn’t quite as quickly install. In my experience DFU (or recovery) is faster esp if you have the macOS image pre downloaded. I usually opt for that even if not strictly necessary and firmware is not bricked.

[dwaite]

Sounds like your issue wasn't with factory resetting, but with the anti-theft features.

The factory reset process is simple. Proving ownership (and transfer of ownership) for getting around anti-theft lockouts is not.