Time Machine is the backup feature built into your Mac: connect a USB or Thunderbolt drive, open System Settings, click General and then Time Machine, choose Add Backup Disk, and it backs up your apps, music, photos, email and documents automatically. From then on it keeps hourly backups for the past 24 hours, daily backups for the past month and weekly backups for every month before that.
Here's the catch. Apple says your backup drive should have at least twice the storage of your Mac, so a Mac with 1TB needs a 2TB disk, and that you should use it only for Time Machine. The whole APFS volume is reserved for backups, and when the disk fills up, Time Machine deletes your oldest backups to make room. If you want one physical drive for backups and other files, use Disk Utility to add a second APFS volume. The two volumes share the space, and the Time Machine one should still be twice the size of your Mac's storage.
Which drives Time Machine can use
| Drive | Works with Time Machine, as of October 2026 |
|---|---|
| External USB or Thunderbolt drive plugged into your Mac | Yes |
| AirPort Time Capsule | Yes |
| Network storage (NAS) that supports Time Machine over SMB or AFP | Yes, and Apple says to pick SMB if you're given the choice |
| One partition of a partitioned disk | Yes, though on a Master Boot Record disk some partitions may not be available |
| iPhone, iPad or iPod | No |
| A disk formatted for Windows | Only after it's reformatted to a Mac format, which permanently removes all its data |
APFS or APFS Encrypted is the preferred format. If the new disk isn't APFS, you're offered the chance to erase and reformat it. A Mac OS Extended disk that already holds a Time Machine backup isn't wiped, and Time Machine still supports Mac OS Extended (Journaled), the case-sensitive version and Xsan disks.
Network drives need a little more care. Some network disks from makers other than Apple don't support Time Machine at all, and if yours doesn't show up in the list of available disks, Apple's advice is to contact the manufacturer. Your Mac must be connected to the SMB server when you set it up. After that, Time Machine reconnects on its own when it's time to back up or restore.
How to set up Time Machine
These steps are for macOS Ventura 13 or later, as of October 2026.
- Connect the drive to your Mac and turn it on.
- From the Apple menu, choose System Settings, click General in the sidebar, then Time Machine.
- Click Add Backup Disk, or the Add button if you already have a backup disk.
- Select the drive and click Set Up Disk.
- Answer the setup questions: whether to erase the drive, whether to claim backups made by a different computer, and whether to turn on Encrypt Backup.
- Let it run. Your Mac starts backing up straight away, and you can choose Back Up Now from the Time Machine menu in the menu bar at any time.
There's a shortcut too. When you plug in a drive and don't have a backup disk yet, your Mac asks if you want to use it with Time Machine. Hold your pointer over that dialog, click Options, then choose Set Up. If you click Close instead, the drive connects as a regular disk.
If you turn on Encrypt Backup, you'll create a backup password, and you'll need it to restore files later. If the Time Machine menu isn't in your menu bar, go to System Settings, click Control Center, scroll to Time Machine and choose Show in Menu Bar.
What gets backed up and how often
| Backup | How long Time Machine keeps it |
|---|---|
| Hourly | The past 24 hours |
| Daily | The past month |
| Weekly | All previous months, until the disk is full |
| Local snapshots | Up to 24 hours, on your Mac's own disk, or until the space is needed |
Time Machine backs up the files that weren't part of the macOS installation, like apps, music, photos and documents. It doesn't back up system files or the apps installed with macOS. Local snapshots are created hourly on APFS disks and let you get back earlier versions of files even when your backup drive isn't plugged in. Apple still recommends a backup somewhere other than your internal disk, so if anything happens to the Mac you can restore your whole system to another one.
The first backup can take longer than you'd expect, but you can keep working while it runs. After that, Time Machine copies only the files that changed, so later backups are faster. To change the schedule, choose Open Time Machine Settings from the Time Machine menu, click Options, and pick a setting from the Back up frequency menu. Before you unplug the drive, eject it or shut down your Mac; Time Machine picks up its schedule again when you reconnect.
Restoring your Mac from a Time Machine backup
To restore everything, including apps and your whole user account, Apple uses Migration Assistant. If you only need a few files or older versions of them, restore those from Time Machine instead. If your Mac starts up to a flashing question mark, reinstall macOS first.
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- Connect the backup drive and turn it on.
- Open Migration Assistant from the Utilities folder in Applications, or with Spotlight. If your Mac is showing the setup assistant, just carry on, because migration is part of setup.
- Choose to transfer from a Mac, Time Machine backup or startup disk, then click Continue.
- Select your backup disk, then pick a backup. Click the disclosure arrow to choose an older one.
- Wait while Migration Assistant works out how much space your information uses.
- Tick the categories you want to transfer and click Continue.
Two things to watch. If you're transferring a standard account, a temporary password appears on screen, so write it down, because that user needs it to log in the first time. And if an account with the same name already exists, you can replace it and, in some cases, keep a copy of the old data in the Deleted Users folder. One more version rule: a backup made on macOS 12 or later can only be restored to a Mac running macOS 11 or later.
Time Machine or iCloud?
They do different jobs. iCloud syncs your photos, videos, contacts, calendars, notes and passwords across devices signed in to the same Apple Account, and iCloud Drive can hold your Desktop and Documents folders, but it uses your iCloud storage plan. Time Machine keeps dated copies of your whole Mac on a drive you own. If your iCloud plan is the thing filling up, here's my guide to clearing space in iCloud.
My verdict on Time Machine
I'd set it up today if you've got a drive at least twice the size of your Mac's storage, and I'd turn on Encrypt Backup and keep that password somewhere other than the Mac. Don't use the backup drive as a dumping ground for other files. And if you're backing up because you're about to sell or hand on the Mac, do the backup first, then follow my steps for wiping a Mac before you sell it.
Frequently asked questions
How big should a Time Machine drive be?
Apple recommends at least twice the storage capacity of your Mac. A Mac with 1TB of storage should ideally have a backup disk of at least 2TB.
How often does Time Machine back up?
It makes hourly backups for the past 24 hours, daily backups for the past month and weekly backups for all previous months. The oldest are deleted when the disk is full.
Can I use my Time Machine drive for other files?
Apple says to use it only for Time Machine. If you need both on one drive, add a second APFS volume in Disk Utility and keep the Time Machine volume twice your Mac's storage.
Can Time Machine back up to an iPhone or a Windows drive?
No. It can't back up to an iPhone, iPad or iPod, and a Windows-formatted disk has to be reformatted for Mac first, which removes all its data.
Does Time Machine back up macOS itself?
No. It doesn't back up system files or the apps installed during macOS installation, only files that weren't part of the installation.
