How to back up a Mac
To back up a Mac you need an external drive and Time Machine, the backup app built into macOS: it copies your files, apps and settings every hour while the drive is connected. A backup lets you get back a deleted or damaged file or move everything to a new Mac, and iCloud Drive doesn’t replace it. This guide covers setting it up and restoring from it.
What you need
- An external USB or Thunderbolt drive, ideally at least twice the size of your Mac’s storage. A network disk that supports Time Machine works too.
- A drive used only for Time Machine. Setting it up may erase what is on it, so move other files off it first.
How to back up a Mac with Time Machine
- Connect the external drive to your Mac.
- Choose Apple menu › System Settings, click General in the sidebar, then click Time Machine.
- Click Add Backup Disk (or the Add button +), select your drive and click Set Up Disk.
- If asked, let Time Machine erase the drive. To protect the backup, turn on Encrypt Backup and create a password. Without that password the backup can’t be restored.
- The first backup starts right away and can take a long time. You can keep working meanwhile. To start a backup at any time, choose Back Up Now from the Time Machine menu in the menu bar.
After that Time Machine keeps hourly backups for the past 24 hours, daily backups for the past month and weekly backups for all earlier months. When the drive fills up, it deletes the oldest ones. Each new backup copies only what changed.
Time Machine doesn’t back up the system files and apps that come with macOS: they come back when you reinstall macOS. Eject the drive before you unplug it. Time Machine also keeps local snapshots on the Mac’s own disk: see how to delete Time Machine backups.
Is iCloud Drive a backup?
Not really. With Desktop & Documents Folders turned on (System Settings › your name › iCloud › Drive), those two folders live in iCloud Drive and sync between your devices. That is sync, not a backup: a file you delete on one device is deleted on all of them. It stays in Recently Deleted for 30 days, then it’s gone.
iCloud Drive is good for having your documents everywhere. Keep a Time Machine backup as well, so a deleted or damaged file can still come back.
How to restore your Mac from a backup
- Connect the Time Machine drive to the Mac.
- On a new or erased Mac, Setup Assistant offers to transfer information. On a Mac already set up, open Applications › Utilities › Migration Assistant.
- Choose to transfer from a Mac, Time Machine backup or startup disk and click Continue.
- Select the backup drive, then the backup you want, and click Continue.
- Select what to transfer: apps, user accounts, files and settings. Click Continue and wait until it finishes.
To get back just one file or an earlier version of it, restore it in Time Machine itself instead of using Migration Assistant.
Keep your Mac tidy
MacWashing doesn’t make backups. Before the first Time Machine backup, System Junk can clear caches hidden inside app data, Xcode junk and leftovers of deleted apps, so there is less to copy.
Free trial · macOS 14 or later
Questions and answers
How big a drive do I need to back up my Mac?
Apple recommends at least twice your Mac’s storage. A bigger drive keeps more old backups before Time Machine has to delete them.
How often does Time Machine back up?
Every hour while the drive is connected. If you unplug the drive, scheduled backups resume when you connect it again.
Can I use the backup drive for other files?
Better not. Apple recommends a drive used only for Time Machine. Advanced users can add a separate APFS volume for other files, but the backups still need their space.