Full-disk encryption (FDE) is a low-effort way to ensure that if someone were to get ahold of one of your drives while unmounted or a Mac while powered down, the contents on the drive would be unusable to them without their knowing a password or other encryption information. Apple offers two distinct ways of encrypting volumes on a drive, and it’s important to know the difference between them and the current limitation on drives connected to M1-based Apple Silicon Macs.
FileVault: FileVault lets you control access to your startup volume, whether on an internal or external drive, including encrypting a drive where necessary. You can’t use FileVault with an external startup drive with an M1-based Mac.
Finder-mountable non-system volumes can be encrypted via the
