How to Use tmutil to Manage Time Machine From the Terminal

Time Machine is one of the few Apple apps where the GUI hides what you actually want. Want to see how big your last backup was? Open the menu bar icon, hover, hope. Want to delete one specific snapshot to recover space? Good luck. Want to exclude a folder you forgot at setup? Buried.

tmutil is the Terminal interface to Time Machine, and it’s where you go when the menu bar isn’t enough.

See what Time Machine is doing right now

tmutil status

If a backup is running, you’ll get a dictionary of fields including Running = 1, Phase, Percent, bytes copied so far, and the total expected bytes. Phase strings like Copying, ThinningPostBackup, MountingBackupVolume tell you which stage you’re in.

If nothing’s running:

{
    Running = 0;
}

For a one-line check you can drop in a script:

tmutil status | grep -q "Running = 1" && echo "Backing up" || echo "Idle"

Start, stop, and skip a backup

tmutil startbackup

Runs a backup right now to whatever destination(s) you’ve configured. Add --block to make the command wait for the backup to finish:

tmutil startbackup --block

That’s useful before a major OS upgrade or before unplugging the backup drive.

tmutil stopbackup

Aborts the current backup. Time Machine will retry on the next scheduled interval.

To skip the next backup without disabling the schedule entirely, there’s no built-in for that — just turn Time Machine off briefly:

sudo tmutil disable
# wait for the moment to pass, then:
sudo tmutil enable

disable and enable toggle the automatic backup schedule. Manual startbackup calls still work either way.

List your backup destinations

tmutil destinationinfo

Outputs a section for every configured backup destination — local disk, network share, multiple drives if you’ve got them. Each has a Name, a Kind (Local, Network), an ID, and a Mount Point.

To add or remove destinations, use System Settings — tmutil can’t add a new destination, only manage existing ones.

Inspect backups on the destination

When the destination is mounted:

tmutil listbackups

You get a list of paths, one per backup, looking like:

/Volumes/Backup/Backups.backupdb/MacBook Pro/2026-04-21-093115

The trailing string is the snapshot timestamp. To see the latest:

tmutil latestbackup

To see how big each backup actually is on disk:

tmutil calculatedrift /Volumes/Backup/Backups.backupdb/MacBook\ Pro/2026-04-20-031022 \
                     /Volumes/Backup/Backups.backupdb/MacBook\ Pro/2026-04-21-093115

That returns the data difference between two backups, which is the closest thing Apple gives you to “how big was that incremental.” Useful for figuring out which backup blew up your disk usage.

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Local snapshots (the hidden disk eater)

Even when your backup drive is unplugged, macOS keeps “local snapshots” of recent backups on your boot drive. They use APFS snapshots, so they cost relatively little — until they don’t.

tmutil listlocalsnapshots /

You’ll see entries like:

com.apple.TimeMachine.2026-04-22-031517.local

To delete one:

sudo tmutil deletelocalsnapshots 2026-04-22-031517

Pass just the date portion (after com.apple.TimeMachine. and before .local).

To wipe all local snapshots in one shot:

for d in $(tmutil listlocalsnapshots / | awk -F'.' '{print $4}'); do
  sudo tmutil deletelocalsnapshots $d
done

macOS will rebuild local snapshots over the next few hours of normal use. They auto-purge when free space drops below a threshold, so you don’t need to delete them manually — but if you’re scrambling to free space right now, this can recover 50+ GB instantly.

Delete a specific full backup

When the destination is plugged in:

sudo tmutil delete -p "/Volumes/Backup/Backups.backupdb/MacBook Pro/2025-01-15-021111"

That removes a full backup. Time Machine will reconcile its index on the next backup. The -p flag specifies a path (post-Sonoma; older syntax used positional args).

For network destinations (.sparsebundle or APFS-style backups), the syntax is the same — tmutil resolves the actual disk paths internally.

Add and remove exclusions

You can exclude paths from being backed up without going into System Settings:

sudo tmutil addexclusion -p ~/Library/Caches
sudo tmutil addexclusion -p /Users/you/VirtualMachines

Use absolute paths. The -p flag means “this path, regardless of where it moves.” Without -p, the exclusion is by path and identity, so moving the file to a new location re-includes it.

Remove an exclusion:

sudo tmutil removeexclusion -p ~/Library/Caches

To list current exclusions:

sudo tmutil isexcluded ~/Library/Caches

That returns whether a specific path is excluded. There’s no built-in “list all exclusions” — you have to check paths one by one. Or grep the underlying property list:

sudo tmutil compare /

compare shows the file-level diff between the running system and the most recent backup, which incidentally surfaces the exclusion list.

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Comparing the live system to a backup

Want to know what you’d lose if you restored right now?

tmutil compare /

That diffs your live system against the latest backup. The output shows file additions, deletions, and modifications, with sizes. Useful before a destructive operation.

You can also compare two specific backups:

tmutil compare /Volumes/Backup/Backups.backupdb/MacBook\ Pro/2026-04-15-031022 \
               /Volumes/Backup/Backups.backupdb/MacBook\ Pro/2026-04-22-031517

This is read-only and doesn’t touch any data — just a diff.

Restore a specific file

tmutil restore /Volumes/Backup/Backups.backupdb/MacBook\ Pro/2026-04-15-031022/Macintosh\ HD/Users/you/Documents/important.pdf \
               /Users/you/Desktop/recovered.pdf

Source first, destination second. The restored file’s metadata (timestamps, ownership, ACLs) is preserved.

This is the headless equivalent of using the Time Machine browser UI to scrub through history and click “Restore.” Faster when you know what you want.

Verify a backup

sudo tmutil verifychecksums /Volumes/Backup/Backups.backupdb/MacBook\ Pro/2026-04-22-031517

Walks the backup and verifies file checksums. Slow — could take hours on a multi-TB backup — but worth running if you suspect bit rot on the destination drive.

What’s eating my backup space?

If your Time Machine destination is filling up faster than you expect, the usual suspect is a single large file that changes constantly. Each change spawns a new copy in the next backup.

tmutil compare /Volumes/Backup/Backups.backupdb/MacBook\ Pro/2026-04-15-031022 \
               /Volumes/Backup/Backups.backupdb/MacBook\ Pro/2026-04-22-031517 | \
  sort -k2 -h | tail -30

Sorts the diff by size. The biggest diffs are the things eating your backups. Common culprits: VM disk images, virtualenv .venv directories, Docker volumes, large .psd files saved hundreds of times. Add them to the exclusion list.

Inheriting backups when migrating Macs

When you replace a MacBook and want the new one to continue using the same Time Machine destination:

sudo tmutil inheritbackup /Volumes/Backup/Backups.backupdb/Old\ Mac

This claims the old Mac’s backups for the new Mac. Used to be necessary; on recent macOS versions Time Machine often handles inheritance automatically, but this is the manual hammer if it doesn’t.

Apple Silicon and APFS specifics

On Apple Silicon Macs and APFS-formatted destinations, Time Machine uses APFS snapshots rather than the older HFS+ hard-link soup. Most tmutil commands work identically, but a few notes:

• tmutil thinlocalsnapshots / runs the snapshot pruner manually. macOS does this automatically when free space gets low.
• tmutil uniquesize <path> returns the unique-to-this-snapshot size for an APFS snapshot. It’s the equivalent of “how much space would I free by deleting just this one?”
• The old Backups.backupdb folder structure is gone on APFS destinations; backups appear as snapshots in /Volumes/<destination>/<machine name>/.

Logging and troubleshooting

Time Machine logs go to the unified log. To see recent activity:

log show --predicate 'subsystem == "com.apple.TimeMachine"' --last 1h

Filter further by adding --info for verbose entries or --debug for everything. Useful when a backup is failing without explanation — the logs almost always tell you why (destination unreachable, permission issue, etc.).

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A reasonable maintenance routine

Once a month:

# Check the most recent backup actually finished
tmutil latestbackup

# Look for crashing local snapshots filling your disk
tmutil listlocalsnapshots / | wc -l

# See if anything new should be excluded
du -sh ~/Library/Containers/* 2>/dev/null | sort -h | tail

Once a year:

sudo tmutil verifychecksums <oldest_backup_path>

Time Machine is mostly fire-and-forget, which is why it’s easy to forget when something quietly went wrong. tmutil status once a week is a 1-second sanity check that catches most “my backup hasn’t happened in three months” situations before you actually need the backup.