[ultrafez]

A fun problem on a Mac is that if you're using APFS for your filesystem, if it fills up, you can't delete any files. It's caught me out a handful of times, and each time, the only way to recover is to reboot, and thankfully I've had more free disk space after a reboot.

I'm not going to try to understand the logic as to why APFS requires free space in order to delete files (via any method, including dd)

[wilsonthewhale]

Probably because it's a log-structured file system, and those _really_ don't like running low on free space.

They work by appending to the log then compacting sometime later, not modifying things in-place. As such, you always need a reasonable supply of free blocks so this can occur.