Backups & restore points · Where backups go
How do I back up to an external drive with Data Backup?
Short answer: Plug the drive in, open the set's Destination menu, choose Choose a folder… and pick the drive. Drive backups are encrypted automatically, with no passphrase to remember.
Connect the drive, then on your backup set open the Destination menu and choose Choose a folder…. Pick the drive (or a folder on it) and the set starts backing up there.
Backups to a drive are encrypted automatically — there's no passphrase to set or remember. Each Mac keeps its backups in its own folder on the drive, named after the computer.
An external SSD is the fastest destination for a big first backup. If the drive isn't connected when a backup is due, the set waits and backs up once the drive is back. See when the drive is unplugged.