Ok, this is driving me crazy.
I migrated an enrolled computer to a new, not enrolled one.
On the enrolled computer, there was a profile defining a custom message below the login fields. When I migrated, even if no profile is on the machine, this text remain.
I added a new text under the Security preferences, which displays when I am already logged in, but the old, managed text, still displays after a restart when no one is logged in, before the disk decryption.
Any clues on how to remove this?
