Time Machine, the Backup Software You Should Be Using

Make automatic backups simple on your Mac

Use Time Machine as the primary backup for your Mac. It's an easy-to-use backup system that restores your Mac to a working state after a crash. It also restores individual files or folders you may have accidentally deleted. In addition to restoring a file, you can go back in time to see what a file looked like at any time or date in the recent past.

Information in this article applies to Time Machine for macOS Catalina (10.15) through Mac OS X Leopard (10.5).

Time Machine's user interface screenshot

About Time Machine

Time Machine is included with all Mac operating systems beginning with OS X Leopard (10.5). It requires an internal or external drive onto which it automatically backs up your Mac as you work.

Time Machine was a revolutionary approach to backup when it was introduced. The revolutionary part wasn't the backup process or how creative the user interface was or how well Time Machine pruned old backups. All these things had been seen before in backup applications. What made Time Machine a winner was that it was so easy to set up and use that people actually used it. With Time Machine, Mac users can back up their computers without thinking about the backup process.

Time Machine backups are not encrypted by default. However, you can choose to encrypt your Time Machine backups.

Set Up Time Machine

Setting up Time Machine amounts to selecting the drive or drive partition you want to dedicate to your backups. Once you do that, Time Machine takes care of almost everything else. Time Machine notifies you when it deletes old backups unless you turn off the notification. You can also add a status icon to the Apple menu bar.

For the most part, that's it. After you select the drive for the backup in the Time Machine system preferences, no other settings are required to set up or configure it. Select Back Up Automatically or turn on the Time Machine switch, depending on the OS version. Then, the system starts backing up automatically.

The Back Up Automatically option

You can access a few options by selecting Options in the Time Machine preferences screen:

  • Exclude files or folders from the backup by entering those in an exclusion list.
  • Allow a Mac laptop to back up while on battery power.
  • Turn off the notification when Time Machine deletes old files.
Options for Time Machine in system preferences

There are other options you can use, such as using multiple drives to store your Time Machine data. However, the advanced settings are hidden and not needed by most casual users.

How Time Machine Performs Backups

The first time it runs, Time Machine performs a full backup of a Mac. Depending on how much data you stored, the first backup can take a while.

After the initial backup, Time Machine performs a backup every hour of any changes that occur. This means you only lose an hour's worth of work in the event of a disaster.

One of Time Machine's benefits is how it manages the space it has for backups. Time Machine saves hourly backups for the last 24 hours. It then saves only daily backups for the past month. For data that's older than a month, it saves weekly backups. This approach helps Time Machine make the best use of available storage space and keeps you from needing tens of terabytes of data to keep a year's worth of backups on hand.

Once the backup drive is full, Time Machine deletes the oldest backup to make room for the newest.

Time Machine doesn't archive data. All data is purged eventually to make room for more recent backups.

User Interface

The user interface consists of two parts: a preference pane for setting up the backups and the Time Machine interface for browsing through backups and restoring data.

The Time Machine interface displays a Finder-type view of your backup data. It then presents the hourly, daily, and weekly backups as stacks of windows behind the most recent backup. You can scroll through the stack to retrieve data from any backup point in time.

Open the Time Machine backup by clicking the Time Machine icon in the Mac Dock.

Mac Dock with Time Machine icon

Scroll backward through time using the time scale on the right side of the Mac screen or the arrow buttons at the right of the stacked desktop screen. Each screen can be navigated, and each file can be viewed. If you find a file you want back on your current-day Mac, select it and click Restore.

Time Machine interface on a Mac