Set the Time Machine Backup Destination with tmutil

Point Time Machine at a backup volume or add a second rotation disk directly from the command line.

macOSbackuptmutiltime-machineMedium risk

Run `sudo tmutil setdestination -a /Volumes/BackupDisk` to add a backup destination, and `tmutil destinationinfo` to inspect the current setup.

01Command

Command

$ sudo tmutil setdestination -a /Volumes/BackupDisk

02What it does

tmutil setdestination accepts a mounted volume path, an AFP/SMB URL, or an APFS share; without `-a` it replaces the sole destination, with `-a` it adds to the rotation set. `tmutil destinationinfo` shows each destination's UUID, which you pass to removedestination to retire one. This is the standard way to script backup setup when provisioning multiple Macs.

03Risk

RiskMedium risk

!Warning: A destination that already contains another Mac's backups will keep them; new backups append without deleting old data.

04Undo

Undo

$ sudo tmutil removedestination <destination-uuid>

05Sources

TCP and UDP ports used by Apple software products - Apple Support
Apple Support · vendor-doc · 2026-09-17
Evidence: Reference for network ports Time Machine uses when backing up over the network to a destination.
TMUTIL Command: macOS Time Machine utility
SS64 · technical · 2026-09-17
Evidence: Documents setdestination (with -a to add a second destination), removedestination, and destinationinfo subcommands.

Last verified: 2026-09-17 · Category: System & Settings

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