How to back up your Mac with Time Machine

Time Machine, the backup tool built into every Mac, saves copies of your files automatically once it is set up with an external drive, so you can bring back a deleted file or recover after a problem. Setup, checking and restoring are covered here.

What you need

• An external drive, such as a USB or Thunderbolt drive. Apple says to use a storage device with at least twice the storage capacity of your Mac. For example, a Mac with 512 GB of storage needs a backup drive of about 1 TB or more.
• A drive used only for backups. Apple advises keeping the drive for Time Machine alone.
• Time. The first backup can take longer than you expect, and you can keep using the Mac while it runs. Later backups copy only what has changed.

Set up Time Machine

macOS Ventura and later

1. Connect the external drive to your Mac.
2. Choose Apple menu then System Settings then General then Time Machine.
3. Click Add Backup Disk (or the Add button).
4. Select your drive, then click Set Up Disk.
5. If your Mac asks you to erase the drive, read the warning above, then confirm only if the drive is empty or you no longer need what is on it.
6. If your Mac asks whether to claim backups made on another computer, choose according to what you want. Claiming makes them part of this Mac's backups.
7. To protect the backup, turn on Encrypt Backup when it is offered, and create a backup password. Write the password down and keep it safe. You need it to restore files.

The first backup starts by itself. On macOS Monterey and earlier, use Apple menu then System Preferences then Time Machine and click Select Backup Disk.

How Time Machine keeps your backups

Apple says 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 disk fills up, the oldest backups are deleted.

• Backups run while the drive is connected and the Mac is on. On a laptop, hourly backups on battery power happen only if you turn on Back up on battery power under Options.
• If macOS itself is damaged, reinstall macOS first, then restore your files from the backup.

Leave out files you do not need

1. Open System Settings then General then Time Machine and click Options.
2. Under Exclude from Backups, click Add and choose a folder or file, such as a large folder of downloads you can get again.
3. Click Remove to take an item off the list later.

Check that it worked

1. Open System Settings then General then Time Machine.
2. Check that your backup disk is listed there. The settings also show the state of the backup, such as the latest one or one in progress.
3. Leave the Mac on and connected until the first backup finishes.

Restore files from a backup

Bring back one file or folder

1. Connect your backup disk and open the folder that held the missing item. For an item that was on the desktop, you do not need to open a window.
2. Open Time Machine. Press Command + Space, type Time Machine and press Return. If a message appears, wait while the Mac connects to the backup disk.
3. Use the arrows beside the windows to move back through earlier backups. The selected backup is highlighted on the timeline at the right.
4. Select the items you want, then click Restore. Restored items return to their original location.

Restore a whole Mac

If macOS was reinstalled or you moved to a new Mac, use Migration Assistant. If macOS cannot start, reinstall it first. See how to reinstall macOS from Recovery.

1. Connect and turn on your backup disk.
2. Open Migration Assistant from the Utilities folder in Applications, or from Spotlight. Enter your administrator password if asked.
3. Choose the option to transfer from a Mac, Time Machine backup or startup disk, then click Continue.
4. Select your Time Machine disk, then choose the backup you want. To use an older one, expand the list.
5. Choose the categories to transfer, then continue and follow the prompts. The transfer can take hours.
6. When it finishes, quit Migration Assistant and log in to the migrated account.

If something goes wrong

• The drive does not appear in the list: try another cable or port, and check that the drive has power if it needs its own adapter.
• The disk is full: Time Machine deletes the oldest backups. If you need more history, use a larger drive. The same lack of space can affect your Mac itself, so see what to do when your Mac storage is full.
• The Mac will not start: your backup is what protects you. See what to try when your Mac will not start.

Frequently asked questions