How to back up your Mac with Time Machine

The feature was introduced with OS X 10.5 Leopard, and it's been there ever since. If you've never used it, Time Machine is one of the easiest ways to back up your Mac, and is great for recovering individual files you've deleted or restoring your entire hard drive in the event of a catastrophe.

How to enable Time Machine backups on your Mac
How to restore files from a Time Machine backup
How to exclude files from Time Machine
How to restore your hard drive from a Time Machine backup

How does Time Machine work?

Time Machine works with any hard disk connected to your computer via USB, FireWire, or Thunderbolt; it also supports Apple's Time Capsule and backup disks connected over a network, provided the disks support Apple File Protocol (AFP) file sharing. As long as the disk is available to your Mac, you can use it for a Time Machine backup.

When enabled, Apple's backup software takes periodic snapshots of all your files and catalogs them on an external hard drive you have plugged in or a Time Capsule you've hooked up to your network. It backs up the entire contents of your hard disk hourly, daily and weekly; as the drive gets full, Time Machine will delete the oldest backups and replace them with newer versions.

This is better than your traditional "Copy a bunch of files to a cloud service" or "clone a disk to an external hard drive" because you don't have to restore your hard drive en masse if you lose a single file—Time Machine can retrieve specific images, folders, and projects from its backup because of its layered snapshot system.

If you're using OS X Yosemite or later on a laptop and enable Time Machine, you'll also automatically get a feature called Local Snapshots; this allows your laptop to back itself up once a day (and once a week) while you're away from your Time Machine drive.

Local Snapshots does take up some of your hard drive with its backups, but if you start to run low, it will automatically purge old backups so that you have at least 20 percent free space on your drive.

Can I exclude data from my backups?

Yup. You can selectively exclude files from your back ups by adding them to a list in the Time Machine Preferences. We've got more on how to do so below.

How to enable Time Machine backups on your Mac

Select System Preferences from the Apple menu.
Choose the Time Machine icon.
Click Select Backup Disk.
Select which disk you'd like to use as a Time Machine backup.
Check the Back Up Automatically box in order to automatically back up your Mac to your chosen disks.

How to restore files from a Time Machine backup

Select System Preferences from the Apple menu.
Choose the Time Machine icon.
Check the box next to Show Time Machine in menu bar.
Click Enter Time Machine after clicking the Time Machine icon in the Menu bar.
Find the file or folder in question and click Restore.

Time Machine will then copy that file back to its original location on your hard drive.

How to exclude files from Time Machine

Time Machine will back up most of your Mac automatically, but you might want to exclude certain files.

Open System Preferences on your Mac.
Click Time Machine.
Click Options….
Click the + button.
Choose the files or folders that you wish to exclude.
Click Exclude.
Click Save.

How to restore your hard drive from a Time Machine backup

Whether you're having major problems with your current hard drive or upgrading to a new Mac, Time Machine can help you get back to business.

Power up your Mac and hold down the Command and R keys to enter the macOS Recovery Partition. Your Mac should boot to a screen that says macOS Utilities.
Select Restore from Time Machine Backup and click Continue.
Read the info on the Restore Your System page and click Continue.
Select your Time Machine backup and click Continue.
Select the most recent backup of your hard disk and click Continue. Your Mac will then restore the Time Machine backup; once it's done it will restart.

If you've had to replace it with a stock drive that has nothing on it—not even macOS—you won't be able to boot from the macOS Recovery Partition. But fear not, you can get the recovery rolling from the Time Machine backup disk itself: Just hold down the Option key when you start your Mac; you'll be able to select the Time Machine backup disk as your startup drive, and go from there.

Let the good times roll

I hope this helps you get going with Time Machine—you never know when you'll have to recover a file or a disk, and it's better to be safe than sorry. Do you use Apple's backup feature? If not, why? Let us know in the comments.

Updated January 2019: Updated for macOS Mojave.

Peter Cohen and Serenity Caldwell contributed to an earlier version of this article.