How to delete old Time Machine backups safely

First identify which disk is full

There are two different places people call “Time Machine storage.” Backups on an external or network destination protect against losing the Mac. Local snapshots live on the Mac itself. This guide covers the backup destination.

Open System Settings › General › Time Machine to identify configured destinations. Check the disk name and whether it's directly attached or on a network. If your Mac's internal storage is full, deleting history from a USB backup drive won't create room on the internal SSD.

For internal snapshots, use the local-snapshots guide. macOS counts their reclaimable space as available and normally manages them automatically. Don't confuse a backup-volume snapshot with a local snapshot of your startup disk.

The safest default: let Time Machine manage old history

Apple says Time Machine keeps recent hourly, daily and older weekly history, deleting the oldest backups when the destination fills. A full backup disk therefore doesn't automatically require manual deletion.

If it still can't complete a backup, Apple's current user guide recommends connecting a new backup disk. A larger destination preserves more history. Apple recommends a device with ideally at least twice the Mac's storage capacity and using it for Time Machine rather than unrelated files.

Before removing anything, confirm a current backup has completed and that you can find important files in the history you intend to retain. A file deleted from your Mac may now exist only in an old backup. “Old” does not mean “unneeded.”

For network storage shared by several people or Macs, consult its administrator before deleting a backup set or changing its quota. Don't erase a shared destination to solve one Mac's capacity problem.

Advanced: delete one dated backup with Apple's tool

Current macOS includes tmutil for managing Time Machine. Its installed manual distinguishes APFS backups from older HFS+ backup folders. Finder folder-deletion instructions written for an older format aren't a general modern procedure.

This permanently removes a restore point. Keep a separate usable backup and verify the destination and timestamp. If you are unsure which volume holds the backup, stop and use the automatic-management or new-disk route instead.

Connect and mount the intended backup destination. Let any active backup finish.
Open Terminal and read man tmutil on your Mac. The syntax below was checked against Apple's installed manual on macOS 27.0.1; no deletion was run for this article.
Use the listing form below, replacing the quoted path with the actual mounted backup volume. This lists timestamps for this Mac's completed backups.

sudo tmutil listbackups -d "/Volumes/Your Backup Disk" -t

The manual requires administrator and Full Disk Access privileges for listing and deletion. If needed, grant Terminal Full Disk Access in System Settings › Privacy & Security; this is broad access. Enter an administrator password only in your own Terminal prompt. You can revoke the permission afterward.

Choose one exact timestamp from the listing, then replace YYYY-MM-DD-HHMMSS below. Do not paste the placeholder as a real date, use a wildcard or guess a backup path.

sudo tmutil delete -d "/Volumes/Your Backup Disk" -t YYYY-MM-DD-HHMMSS

Apple's manual says this command can delete backups belonging to another Mac too, which makes checking the target essential. The -p path form is specific to HFS backup disks; it isn't a substitute for the APFS timestamp form.

Do not use rm -rf on the backup hierarchy or change its ownership to force a deletion. If the documented tool fails, keep the error message and seek help rather than escalating file-removal commands.

If you want to remove all backups from an old disk

Erasing is appropriate only when you deliberately want to retire or start over with the entire selected destination. Copy any other needed files elsewhere and retain a separate completed backup first.

In Time Machine settings, remove the old destination using the remove control and Forget Destination. This changes the backup configuration; it isn't a secure erase or selective-history command.
Open Disk Utility, choose View › Show All Devices, and identify the intended external device by name and capacity.
If you intend to erase the whole physical device, select that device and use Erase. Apple documents GUID Partition Map and a chosen filesystem; APFS is the current Time Machine format recommendation.
Read the target and deletion warning before confirming. Erasing the device removes all volumes and data on it, not just one Mac's backup.
To reuse it, add it in Time Machine settings and let a new full backup complete.

If the disk contains other volumes you need, don't select the whole physical device. Get volume-specific advice rather than treating the above whole-disk procedure as selective deletion.

Reduce future backup growth

Time Machine settings includes Options › Exclude from Backups. Excluding an item means future Time Machine backups won't protect it. Use this only for files you can recreate or that have a separate backup, and don't expect it to be a selective deletion of every historical copy.

Apple notes that large frequently changing files can slow backups. If speed is the issue, its troubleshooting starts with factors such as connection, other apps and disk format. Reformatting an old HFS+ destination as APFS deletes its existing contents; it isn't a lossless speed switch.

After any deliberate cleanup, verify the next backup completes. Deletion has solved little if you are left with free space but no usable current backup.

How Tend helps

Tend can show local snapshots for free; Pro can remove them after confirmation, permanently. Those are snapshots on the Mac. Tend doesn't manage or delete Time Machine backups on the external or network backup disk.

Questions

Should I manually delete old Time Machine backups?

Usually no. Time Machine automatically removes the oldest backups as its disk fills. Apple recommends a new backup disk if you still run out of room. Manual deletion sacrifices restore history.

Will deleting external backups free space on my Mac?

No. It frees space on that backup destination. For internal storage, investigate files and local snapshots on the Mac instead.

Does Forget Destination delete the backups?

It removes that destination from Time Machine configuration. Treat deleting dated backups or erasing the disk as separate operations; forgetting is not a secure erase.

Can I delete backup folders in Finder?

Do not treat old folder-based instructions as a general APFS procedure. Use Time Machine’s automatic management or Apple’s documented tmutil operation after verifying the target and preserving needed history.