Hi all Have posted already about this but just thought I would warn people of a potential new feature of FileVault, I have spoke to apple support and they have confirmed this is a security feature of FileVault. Basically if you leave FileVault enabled before booting into recovery, unlocking your disk and erasing it then reinstalling macOS to prepare your Mac for a re-sale, during the set up process it will request your old password as the disc was previously encrypted, which leaves a new owner unable to set up the Mac. This should not happen if FileVault is disabled before restoring your Mac. I spoke to apple support and they confirmed this is normal and it is a security feature (similar to activation lock on iOS), however there is no mention of it on apples support pages. If anyone can confirm this also happens with them with Mojave it would be great to find a workaround.