To delete Time Machine backups safely, start with the fact that you rarely need to. Time Machine deletes the oldest backups by itself when the backup disk is full, and keeps fewer of them as they age. Deleting backups by hand frees space on the backup disk only, never on your Mac.
When you do need to, for a disk you want back, an old Mac's backups or a fresh start, the way Apple documents for macOS 26 Tahoe and macOS 27 Golden Gate is blunt: erase the backup disk in Disk Utility and set it up again. Removing single backups is possible, but Apple's current guide no longer describes it.
If it's your Mac's own disk that's short of space, this post isn't the one you need. That space is held by local snapshots, which live on your Mac and come and go by themselves. The post on Time Machine's local snapshots on your Mac covers them.
Almost every way to delete backups is permanent. An erase can't be undone, and on modern backup disks a deleted backup skips the Trash. So the order here is: know what you're deleting, keep what you might need, then pick the gentlest method that does the job.
Backups on the backup disk, or snapshots on your Mac?
Time Machine keeps two different things, in two different places, and advice online often mixes them up. Getting this right first saves you from deleting history you wanted to keep while the space you needed stays used.
| Local snapshots | Backups | |
|---|---|---|
| Where they live | Your Mac's own disk | The backup disk or network destination |
| How long they stay | About 24 hours, plus the last successful backup | Hourly, daily and weekly, until the disk fills |
| Who removes them | Time Machine, as they age or space is needed | Time Machine, oldest first, when the disk is full |
| What deleting frees | Space on your Mac | Space on the backup disk only |
| Covered in | The local snapshots guide | This post |
How do you tell which one is using space?
Look at which disk is full. If System Settings › General › Storage shows your Mac nearly full with a large System Data figure, and you back up with Time Machine, local snapshots are the likely reason. The guide to local snapshots shows how to see and remove them.
If the backup disk itself shows as full in Finder, that's backups. It's also normal, as the next section explains.
Does deleting backups free space on your Mac?
No. Backups on an external disk or a network destination use that disk's space. Deleting them, all of them even, gives back nothing on your Mac and removes history you might need later.
The one exception is a Mac that other Macs back up to over the network. Their backups sit in a shared folder on that Mac's disk, and removing them does free space there. That case has its own section below.
Are the snapshots on the backup disk the same thing?
Not quite. On a backup disk formatted as APFS, each backup is stored as a snapshot of the backup volume. Disk Utility can list them, much as it lists local snapshots on your Mac. They're backups, though, with your history in them, not short-lived copies.
If you open Disk Utility to remove snapshots, check which volume is selected. Snapshots on Macintosh HD – Data are local snapshots; snapshots on the backup volume are your backups. The post on how APFS snapshots work explains the difference in more depth.
How Time Machine already deletes old backups
Time Machine is built to fill its disk with history and then manage that history itself. Apple's description is short: Time Machine makes hourly backups for the past 24 hours, daily backups for the past month and weekly backups for all previous months. The oldest backups are deleted when your backup disk is full.
What does Time Machine keep as backups age?
Fewer of them. An hour-by-hour history is kept for a day, then one backup a day for a month, then one a week from then on. The backups in between are removed as they age, so a year-old history costs much less space than a year of hourly backups would.
Apple doesn't document which backup of each day or week survives. In practice, what matters is that you can go back a long way, with less detail the further back you go.
| Age of the backup | What Time Machine keeps |
|---|---|
| The past 24 hours | One backup an hour |
| The past month | One backup a day |
| Older than a month | One backup a week |
| The oldest weeks, once the disk is full | Deleted to make room |
What happens when the backup disk is full?
Time Machine deletes the oldest backups to make room for the new one. Apple adds that if Time Machine needs more storage space, your Mac lets you know. That's the moment a decision is yours, not before.
When the next backup is larger than what deleting old ones can free, Time Machine can't complete it. The post on a Time Machine backup disk that's full goes through those messages and the fixes, from excluding items to a bigger disk.
Why does the backup disk always look full?
Because that's how Time Machine uses it. A disk that's been in use for a while is close to full most of the time, with the oldest weekly backups at the edge waiting to be removed. That's history, not waste.
Deleting backups to make the disk look emptier only shortens how far back you can go. Time Machine will fill the space again.
Can you see how far back your backups go?
Yes. Open the folder you care about in Finder, then open Time Machine with Spotlight. Apple's guide says to use the arrows next to the Finder windows to move through your backups; the timeline on the right shows the dates you can go back to, with the current one in red.
The oldest date there is how far your history reaches. If it's further back than you'll ever need, a smaller disk would have done; if it's too recent, the disk is too small for your Mac.
When should you delete Time Machine backups yourself?
Most people never need to. There are a few good reasons, though, and each one points to a different method.
You want the disk back for something else
A backup disk you no longer use for Time Machine is just a disk once its backups are gone. Erasing it in Disk Utility is the clean way to get all of it back. If you want a disk for both backups and files, the better plan is two APFS volumes, covered below.
The backups belong to a Mac you no longer have
An old Mac's backups can be worth keeping for a while, in case you find something missing on the new one. Once you're sure, removing them is reasonable. How depends on the disk's format and whether that Mac had its own volume.
You want a file gone from every backup
Sometimes a file shouldn't be kept at all: a document you were asked to destroy, or a folder of personal data. On a Mac OS Extended backup disk, Time Machine had a command for exactly this. On an APFS backup disk, the only complete answer is to remove the backups that hold it.
Backups keep failing
Apple's troubleshooting article lists erasing the backup disk and selecting it again in Time Machine as a last step, when repairs and other fixes haven't helped. Try the other steps first, because this removes the whole history.
When not to delete backups
- To free your Mac's own space. It frees nothing there.
- Because the disk shows as full. That's normal, and Time Machine handles it.
- Before a cleanup. Old backups are exactly what saves you if a cleanup goes wrong; the checklist for backing up before a cleanup covers that.
- To speed anything up. Fewer backups don't make your Mac faster.
Before you delete any backups
Deleting backups can't be undone, so a few minutes of checking first is worth it.
Is anything only in the old backups?
A backup holds files you've since deleted from your Mac. If you delete the backups, those files are gone too. Think about projects you removed, an old Photos library, or documents from a past job.
To check, open the folder in Finder, open Time Machine and go back to a date before you made the change. Select what you want and click Restore. Apple's guide says restored items return to their original location, so a file from Documents goes back to Documents.
Which Macs back up to this disk?
A disk used by more than one Mac holds every Mac's history. Before erasing it, ask whoever owns the other Macs. Their backups may be the only copy of their files.
Is something else stored on the disk?
Apple recommends using a Time Machine disk only for Time Machine. If you, or someone else, kept files on it anyway, erasing the disk removes those too. Copy them somewhere first, or delete only the Time Machine volume if they're on a volume of their own.
Do you have a current backup somewhere else?
If you're about to erase your only backup disk, your Mac has no backup until the new first backup finishes. That can take hours. A second disk, even a borrowed one, closes that gap: back up to it first, then erase the old one.
What each method takes away
| Method | What goes | Can you undo it? |
|---|---|---|
| Let Time Machine manage it | The oldest backups, only when needed | Not needed |
| Forget Destination | Nothing; the backups stay on the disk | Yes, add the disk again |
| Erase the disk or volume | Every backup on it | No |
| Delete one backup on APFS | That backup | No, it skips the Trash |
| Delete one Mac's folder on Mac OS Extended | That Mac's whole history | Only while it's still in the Trash |
| Delete All Backups of an item | Every copy of that item | No |
Start over: erase the backup disk in Disk Utility
This is the method Apple describes today, and it's the most reliable one. Everything on the disk goes, and Time Machine starts a fresh history on it.
How do you erase a Time Machine disk?
- Wait for any backup in progress to finish. The Time Machine menu in the menu bar shows when one is running.
- Open Disk Utility, in the Utilities folder of your Applications folder, and choose View › Show All Devices.
- Select the backup disk in the sidebar. Check its name and size carefully; erasing the wrong disk is the costly mistake here.
- Click Erase. Enter a name, choose APFS from the Format menu and GUID Partition Map from the Scheme menu, then click Erase.
- Click Done when it finishes.
Apple's Disk Utility guide is plain about step 4: erasing a storage device deletes everything on it.
How do you set the erased disk up again?
- Choose Apple menu › System Settings, click General, then Time Machine.
- If the old disk is still listed, select it, click the remove button and choose Forget Destination.
- Click Add Backup Disk, or the add button, select the erased disk and click Set Up Disk.
- Choose whether to encrypt the backup. If you do, you'll set a password you'll need to restore.
Time Machine starts backing up right away. Apple notes the first backup can take longer than you expect, and later backups are faster because they copy only what changed.
Should you erase the whole disk or one volume?
If the disk has only Time Machine on it, erase the whole device as above. If it also has a volume with your own files, erase only the Time Machine volume: select that volume rather than the device, and click Erase. Apple's guide says the empty volume stays in its container, and the other volumes keep their data.
The post on Disk Utility for storage explains devices, containers and volumes, and how to tell which one you've selected.
Is it worth erasing an old Mac OS Extended backup disk?
Sometimes. Apple's article on slow backups suggests that if your backup disk isn't APFS, you can erase it as APFS for better performance on macOS Big Sur or later, warning that this permanently deletes any backups on it. To check, select the disk in Finder and choose File › Get Info; the Format field shows it.
Apple still supports Mac OS Extended backup disks, and doesn't ask you to erase one that already holds backups. The post on APFS, Mac OS Extended and exFAT compares the formats.
What about encrypted Mac OS Extended backup disks?
Apple has announced that in macOS 28 and later, Mac OS Extended will be supported only on volumes that aren't encrypted. Its conversion and decryption steps don't apply to encrypted Time Machine backup disks, and it offers no separate fix for them.
So an encrypted Mac OS Extended backup disk is one to replace before then, with a new APFS backup, encrypted if you like. Keep the old disk until you're sure you won't need its history.
Delete one backup or one item: what works on each disk format
Apple's current Mac User Guide doesn't describe deleting individual backups. The page that did, "Delete a file from your Time Machine backup disk", appears in the guides for macOS Catalina and earlier. What you can do depends on how your backup disk is formatted.
On a Mac OS Extended backup disk
Backups made by macOS Catalina and earlier, and some later ones that kept their old disk, sit in a folder called Backups.backupdb. Apple's Catalina guide described two ways to remove things there:
- Every copy of one item: in Time Machine, select the item, click the Action pop-up menu, then choose Delete All Backups of the item. Apple notes this applies only to backups on an external backup disk.
- Whole backups or a Mac's folder: use the Finder to delete folders inside Backups.backupdb, but not individual items inside the dated folders.
The same page warns: don't use Terminal or any app other than the Finder to move, copy or remove items in Backups.backupdb. Whether the Delete All Backups of command still appears on a given macOS version isn't documented now.
On an APFS backup disk
Since macOS Big Sur, Time Machine backs up to APFS, and each backup is a read-only snapshot. Howard Oakley of Eclectic Light explains the consequence: you can't delete a file or folder inside a backup. You can only delete whole backups.
He describes two ways to do it. In Finder, open the backup volume, select a backup, Control-click it and choose the command that deletes it immediately. It doesn't go through the Trash, so it can't be recovered. Disk Utility's list of the backup volume's snapshots is the other way.
How do you delete a backup in Disk Utility?
- Connect the backup disk and open Disk Utility.
- Choose View › Show APFS Snapshots, then select the backup volume in the sidebar, not your Mac's own volume.
- Select the backup you want to remove in the list at the bottom, and click the Delete Snapshot button.
- Choose View › Hide APFS Snapshots when you're done.
Apple's Disk Utility guide documents deleting snapshots on any selected volume, though it doesn't mention Time Machine backups by name.
Is it safe to delete a single backup?
It isn't the supported path, and people who answer Time Machine questions on Apple's forums advise against it for routine use. Time Machine expects to manage its own history. If you do it, keep it small and careful:
- Delete the oldest backups, never the most recent one, which is your newest way back.
- Don't do it while a backup is running.
- Check the backup's date twice before you confirm.
Which methods work on your disk?
| What you want | Mac OS Extended disk | APFS disk |
|---|---|---|
| Remove every copy of one file | Delete All Backups of, in Time Machine | Not possible |
| Remove one whole backup | Finder, a dated folder | Finder or Disk Utility, permanently |
| Remove one Mac's backups | Finder, that Mac's folder | Delete that Mac's volume, if it has one |
| Remove everything | Erase in Disk Utility | Erase in Disk Utility |
| Keep a file out from now on | Exclude from Backups | Exclude from Backups |
Keep the file out of future backups
Whichever format you have, deleting a file from old backups only matters if it stays out of new ones. Open System Settings › General › Time Machine, click Options, and add the file or folder to the list. The post on excluding folders from Time Machine goes through the list in detail.
Removing one Mac's backups from a shared disk
Families and small offices often back several Macs up to one disk. Removing one Mac's history without touching the others takes a little planning.
Two Macs on one external disk
On an APFS disk, Apple says the whole APFS volume is reserved for Time Machine backups. If each Mac was set up with its own volume, removing one Mac's history is simple: select that Mac's volume in Disk Utility and click Delete Volume. Apple's guide says the volume's data is permanently erased and the others are untouched.
If the Macs share one volume, Apple doesn't document a way to remove one Mac's backups from it. Leave them for Time Machine to age out, or start the disk over.
What about a Mac OS Extended disk shared by two Macs?
Inside Backups.backupdb, each Mac has its own folder, named after the Mac. Apple's Catalina guide allows deleting folders there with the Finder, so moving the old Mac's folder to the Trash removes its whole history.
Expect emptying the Trash to take a long time, with a very large number of items. If it stalls or refuses, the post on a Trash that won't empty covers the usual causes.
A Mac shared as a network backup destination
If other Macs back up to a folder you share in System Settings › General › Sharing, their backups take real space on your Mac. Ask the owner first, and have them remove the destination in their own Time Machine settings with Forget Destination.
Network backups are stored in a disk image, one for each Mac, inside the shared folder and usually named after that Mac. Apple doesn't document deleting one. It's an ordinary item on your disk, though: moving it to the Trash removes every backup inside it, and the space comes back when you empty the Trash.
Can you limit it instead of deleting?
Yes, if the other Mac still backs up to you. In the Shared Folders list, Control-click the folder, choose Advanced Options and turn on Limit backups to, with a size. Time Machine then works within that size, removing the oldest backups as it does on any full disk.
Backups on a NAS
A network storage device that supports Time Machine over SMB holds each Mac's backups in a disk image on a share. The NAS's own admin app or web page is the place to remove a share or its contents, as your NAS maker's documentation describes. Deleting a large backup over the network from Finder can take a very long time.
Apple says Time Machine to a NAS over AFP isn't supported in macOS 27 or later. If an old NAS only offered AFP, a Mac on macOS 27 can't reach those backups at all, so there's nothing to delete from your Mac's side.
And a Time Capsule?
AirPort Time Capsules use AFP too, which Apple says isn't supported in macOS 27 or later. Leave the old backups on it for as long as you might want them, and read them from a Mac still on an earlier version of macOS if you need something.
A worked example: retiring an old Mac's backups
Say a 4 TB backup disk has served two Macs for years: an iMac still in daily use, and an old MacBook Pro that's since been sold. When the disk was set up, each Mac got its own APFS volume on it, so each has its own history.
What gets checked first
The MacBook's owner moved to a new Mac with Migration Assistant months ago. Before anything goes, they connect the disk to the new Mac, open the old MacBook's backup volume in Finder and look through its most recent backup for anything that didn't come across: a folder of scans, an old project.
Two small folders turn up. They drag copies out of the backup to the new Mac's Documents folder. That's the last time anyone will need the old volume.
Removing the old Mac's volume
- In Disk Utility, choose View › Show All Devices.
- Under the backup disk, select the old MacBook's volume. Its name and the size it uses confirm it's the right one.
- Click Delete Volume, then Delete, and Done when it finishes.
The iMac's volume, in the same container, isn't touched. Its backups, its settings in Time Machine and its history all stay as they were.
What they don't do
They don't erase the whole disk, which would take the iMac's history with it. They don't delete the old volume's backups one at a time either, which would take far longer and end in the same place.
The result
Volumes in one APFS container share its free space, so the iMac's Time Machine volume now has much more room to grow into. Over the following months, Time Machine keeps more of the iMac's old weekly backups before it needs to delete any.
Retire a backup disk instead of emptying it
Often the best way to "delete" old backups is to stop adding to them and put the disk in a drawer.
Forget a destination without erasing it
In System Settings › General › Time Machine, select the disk, click the remove button and choose Forget Destination. Time Machine stops trying to back up to it. The backups stay on the disk, readable whenever you connect it.
Moving to a bigger disk
Apple doesn't offer a way to copy Time Machine backups from one disk to another, and Oakley notes that APFS backup snapshots can't be copied or moved. So the move is: set up the new disk, let its first backup finish, and keep the old disk as an archive.
After a few months, when you're confident you won't need the old history, erase the old disk and use it for something else.
Using two disks in turn
Apple's guide says Time Machine can back up to more than one disk and rotates its schedule among them, backing up to each everything that changed since that disk was last used. One disk at home and one elsewhere is a sturdy setup, and each disk keeps its own history.
What if the disk itself is the problem?
If a backup disk is acting up, Apple's article suggests repairing it with Disk Utility before erasing. If a disk full of backups shows less space than expected, or none at all, the post on an external drive that's full with no files explains where the space can hide.
Mistakes to avoid when deleting backups
Most backup disasters start with an action that seemed tidy at the time.
Deleting backups to make room on your Mac
It doesn't work, and it costs you history. Your Mac's space is in local snapshots, caches or your own files, never on the backup disk.
Using Terminal commands from a web page
Time Machine has a command-line tool. It's command-line only, with no window or menu, and a mistyped command can remove backups you meant to keep. Everything in this post goes through Time Machine, Finder and Disk Utility, which is what Apple's own steps use.
Letting other apps clean the backup disk
Apple's older guide says to use only the Finder in Backups.backupdb. Any app that "cleans" a backup disk works outside what Time Machine expects, and a damaged backup can be worse than an old one.
Erasing the wrong disk
Disk Utility erases whatever is selected. Check the name, the size and the connection before you click, and disconnect other external disks if you can.
Deleting your only backup before the new one exists
Back up to a second disk first, or accept a few hours with no backup while the new first backup runs. Don't erase the old disk the day you buy a new one.
Forgetting where the space went
After deleting backups on an APFS disk, the free space can take a moment to show. If it still looks wrong after a while, run First Aid on the disk in Disk Utility.
How the app does it
Wombit shows what's using your Mac's storage, explains every item in plain language, and clears it safely: Trash first, undoable and logged. File names and paths never leave your Mac.
It never touches the backups on your Time Machine disk. What it shows is the Time Machine space on your Mac itself: its space meter shows how much of the available space is purgeable and how many local snapshots there are, and System Data, explained gives local snapshots a bucket of their own.
The Local Snapshots page lists every snapshot: when it was made, which app made it, and whether macOS removes it by itself.
Hourly snapshots of your startup disk that Time Machine keeps on the disk itself, so you can restore files even without your backup disk.
Managed by macOS · Runs tmutil for Time Machine's own snapshots, through the helper
Local snapshots are Managed by macOS: explained and handled through macOS's own mechanism, never moved to the Trash. When you choose, the app deletes Time Machine's own snapshots with Time Machine's own tool, or asks Time Machine to remove as many as it can, with an administrator's name and password through the helper.
Seeing your snapshots is free. Removing Time Machine snapshots is PRO: one payment of $4.99 with lifetime access. Every Pro tool's review is free to open, so you see what would go and why before you buy.
Frequently asked questions
Does Time Machine delete old backups automatically?
Yes. Apple says Time Machine keeps hourly backups for the past 24 hours, daily backups for the past month and weekly backups for all previous months, and deletes the oldest backups when the backup disk is full. A full backup disk is normal, not a problem to fix.
Will deleting Time Machine backups free space on my Mac?
No. Backups live on the backup disk, so deleting them frees space there only. If your Mac's own disk is short of space because of Time Machine, the cause is local snapshots, which Time Machine manages separately on your Mac.
Can I delete a single file from all my Time Machine backups?
On an older Mac OS Extended backup disk, Apple's guide for macOS Catalina describes Delete All Backups of an item, in the Action menu inside Time Machine. On an APFS backup disk, each backup is a read-only snapshot, so single items can't be removed. Exclude the item from future backups instead.
What is the safest way to delete all Time Machine backups?
Erase the backup disk, or its Time Machine volume, in Disk Utility, then set it up again in Time Machine settings. Apple suggests this as a last resort when backups fail. It's permanent, so make a new backup elsewhere first if you might need any of the old history.
Can I drag old Time Machine backups to the Trash?
On a Mac OS Extended backup disk, Apple's older guide says you can delete folders inside Backups.backupdb with the Finder, but never items inside the dated folders. On APFS backup disks, the Finder deletes a whole backup immediately, without the Trash. Neither is needed for normal use, because Time Machine removes old backups itself.
How do I remove an old Mac's backups from my Time Machine disk?
If that Mac had its own APFS volume on the disk, delete that volume in Disk Utility. On a Mac OS Extended disk, each Mac has its own folder inside Backups.backupdb. Make sure no one still needs those backups, since they may be the only copy of that Mac's files.
Does removing a backup disk from Time Machine settings delete the backups?
No. Forget Destination only stops Time Machine from using the disk. The backups stay on it, and you can still restore from them by connecting the disk later. Erase the disk in Disk Utility if you want them gone.
Sources
- Back up your Mac with Time Machine · Apple
- Delete a file from your Time Machine backup disk (macOS Catalina) · Apple
- If you can't back up or restore your Mac using Time Machine · Apple
- If Time Machine takes a long time to back up · Apple
- Add, delete, or erase APFS volumes in Disk Utility on Mac · Apple
- What can you do with Time Machine backups on APFS? · Eclectic Light