I know of two ways to enable full-disk encryption in macOS Sierra:
- Turn on FileVault 2, or
- Boot to recovery, reformat the disk as encrypted, and reinstall macOS.
I've read in several places around the web that the underlying encryption technology is the same either way, and the difference is just how the decryption key is obtained at boot time. With FileVault, a user's login password also serves to unlock the disk, but when you encrypt with Disk Utility, you choose a separate password just for the encryption.
I've found that if the disk was encrypted via Disk Utility at install time, you can also enable a user to unlock it via the FileVault preferences window. Then, at startup, you can unlock the disk using either the disk password or the user's login password.
Having gotten into this hybrid state, though, I don't see a way to get out of it. What I'd like to know is:
- After I've enabled a user to unlock the disk, is there a way to remove the old disk password (that was created with Disk Utility at install time) and replace it with a recovery key, so it's like a normal FileVault setup that just uses user passwords?
- Alternatively, is there a way to remove the user from FileVault so that only the disk password will work?
And, on a related note:
- If FileVault was enabled in the usual way (starting from an unencrypted Mac), is there a way to add a disk password that's separate from the user login passwords, like what I'd have if I'd encrypted via Disk Utility at install time?