Mac Basics: Time Machine
Learn how to set up Time Machine to perform backups, how to restore items, how to use System Restore to return your entire Mac to a specific date, how to migrate backups to a new Mac, and more.
Time Machine is the built-in backup that works with your Mac and an external drive (sold separately) or AirPort Time Capsule. Connect the drive, tell Time Machine to use it, and relax. Time Machine automatically backs up your entire Mac, including system files, applications, accounts, preferences, email messages, music, photos, movies, and documents. But what makes Time Machine different from other backup applications is that it not only keeps a spare copy of every file, it remembers how your system looked on any given day—so you can revisit your Mac as it appeared in the past. Time Machine keeps hourly backups for the past 24 hours, daily backups for the past month, and weekly backups until your backup drive is full.
OS X Lion lets you:
- Encrypt your Time Machine backup drive using FileVault 2.
OS X Mountain Lion lets you:
- Encrypt AirPort Time Capsule backups and network backups using FileVault 2.
- Select multiple backup destinations that Time Machine will rotate through for backup cycles.
- Complete backups when the Mac is in Power Nap (on compatible Macs).
Setting up Time Machine backups using an external drive
Setting up Time Machine is as easy as connecting an external drive to your Mac via Thunderbolt, FireWire or USB.
If you haven't specified a Time Machine backup device and you connect an external drive, Time Machine will display a dialog similar to this one:
Note: The "My Backup (489.5 GB)" text in the above example, will be replaced with the name and capacity of the external drive you connect.
Click "Use as Backup Disk" to confirm you want to use the drive for Time Machine backups. Time Machine preferences will then open with this drive selected as your backup destination.
Check "Encrypt Backup Disk" if you want to encrypt the Time Machine backup external drive using FileVault 2 (OS X Lion and later).
That's all you have to do for Time Machine to automatically backup your Mac. The Time Machine pane of System Preferences will look similar to this.
Note: The "My Backup" and drive capacity in the above example will be replaced with the name and capacity of the external drive you configured as your Time Machine backup.
Manually preparing a new disk for Time Machine
- If you want to erase a disk before using it with Time Machine, follow these steps:
- Open Disk Utility (located in the Utilities folder).
- Connect the disk if it isn't already attached.
- In the left side of the Disk Utility window, select the disk you want to use with Time Machine.
- Optional: If you want to partition the disk, click the Partition tab and select a layout. Make sure "Mac OS Extended (Journaled)" is selected in the Format menu for the partition that will be used for backups. Click Apply.
- Click the Erase tab.
- Optional: If you want to securely erase the disk, click Security Options to configure, then click OK.
- Click Erase.
- After erasing, open Time Machine preferences in System Preferences and configure as described in the section above.
About the first backup to an external drive
You may want to set up Time Machine in the evening so that the initial backup can be done overnight because it may take a while depending on the size of your OS X volume. You should not interrupt the initial backup. You can continue to use your Mac while Time Machine backs up.
Once the initial backup is completed, Time Machine performs subsequent hourly backups of only the files that have changed on your Mac since the last backup (as long as your backup drive is connected).
Tip: You can manually initiate a Time Machine backup cycle at any time by choosing Back up Now from the Time Machine menu, even if you have Time Machine preferences set to off.
Manually selecting a backup drive
You can manually select a backup drive in the Time Machine pane of System Preferences.
- Choose Time Machine menu > Open Time Machine Preferences…
- If the padlock in the lower left is locked, click it and enter an administrator name and password to unlock.
- Click Select Disk….
- Select a drive, then click Use Disk.
Note: In OS X Mountain Lion and later, if a backup device is already selected, you will be prompted to click one of these options:
- Cancel - This will cancel the process and leave your Time Machine settings as is.
- Replace (current drive name) - Time Machine will stop using the current drive and replace it with the new selection.
- Use Both - Time Machine will cycle backups through multiple backup devices. See the "Setting up an additional Time Machine backup (OS X Mountain Lion or later)" below for details.
Important: Every available drive that can be used to store backups is listed. If you’ve partitioned a drive, the available partitions are listed. Time Machine can’t back up to an external drive that's connected to an AirPort Extreme or a drive formatted for Microsoft Windows (NTFS or FAT format). If you select an NTFS or FAT-formatted drive, Time Machine prompts you to reformat the drive. Choose a different drive or reformat the drive in Mac OS Extended (Journaled) format. Because reformatting erases any files on the drive, only do this if you no longer need the files or if you have copies of them on a different drive.
The most common format for a Time Machine backup drive is Mac OS Extended (Journaled) format, but Time Machine also supports Mac OS Extended (Case sensitive, Journaled) and XSan formats.
If the drive is partitioned using the Master Boot Record (MBR) partition type, some partitions may not be available for use with Time Machine. The GUID Partition Table (GPT) type is recommended.
Time Machine works best if you use your backup drive only for Time Machine backups. If you keep files on your backup drive, Time Machine won’t backup those files and the space available for Time Machine backups will be reduced.
OS X Mountain Lion, OS X Lion v10.7.2 and later: Starting from the recovery partition of a Time Machine backup drive
Hold down the Option key at startup to boot into the startup manager. Select the Recovery system of the Time Machine backup to start from. Once started, you will have all of the functionality of Recovery.
Setting up Time Machine for backups using AirPort Time Capsule
If you have an AirPort Time Capsule on your home network, you can use it as your Time Machine backup device. See the documentation that came with your AirPort Time Capsule for information about setting it up on your home network.
Once your AirPort Time Capsule has been configured for your home network, open Time Machine preferences and click "Select Disk…".
From the sheet that appears, select the AirPort Time Capsule you would like to use for backup.
Tip: Click "Set up Other Time Capsule" to open your AirPort utility to setup and configure your AirPort Time Capsule. Enter the name and password or password only that you set for your AirPort Time Capsule via the Airport Utility.
OS X Mountain Lion or later: Check "Encrypt backups" to use FileVault 2 to encrypt the backup on the AirPort Time Capsule.
About the first back up to AirPort Time Capsule
Once the initial backup is completed, Time Machine performs subsequent hourly backups of only the files that have changed on your Mac since the last backup (as long as your Mac is awake and the backup drive is connected).
Tip: You can manually initiate a Time Machine backup cycle by selecting "Back up Now" from the Time Machine menu, even if you have Time Machine preferences set to off.
Setting up an additional Time Machine backup (OS X Mountain Lion)
Time Machine in OS X Mountain Lion allows you to add an additional Time Machine backup destination to your existing Time Machine backup destination list. You can use this to have an extra Time Machine backup and or have another Time Machine backup at another location. For example, you can have a Time Machine backup destination at home and a backup destination at work.
Simply add an external drive or AirPort Time Capsule using the Time Machine pane of System Preferences with the steps detailed above.
Once configured, Time Machine will rotate backup cycles across the configured Time Machine backup destinations. If a destination cannot be found at the time of the backup cycle, Time Machine will skip that backup destination. Time Machine will try the next backup destination on the list until it can find a backup destination to interact with and complete a backup.
Selecting items to exclude from the backup
In Time Machine preferences you can click the Options button to adjust settings. A sheet similar to this appears when you click Options:
This sheet allows you to exclude files, folders, or entire volumes from being backed up. You might want to do this to avoid filling up your backup drive.
Tip: If you regularly modify a very large file (greater than 1 GB, for example), you might want to add that specific file to the "Exclude these items from backups" list. Time Machine backs up modified files, regardless of how much or how little the file changed from the previous backup.
The "Notify after old backups are deleted" option tells Time Machine to warn you when older backups are removed from your backup drive to make space for more recent backups.
Restoring data from Time Machine backups
With Time Machine you can go "back in time" to restore files, versions of files, or your entire system. Make sure your backup drive is connected and mounted (if not, Time Machine will alert you that "Your Time Machine backup disk can't be found."
Restoring specific files or folders
Choose Enter Time Machine from the Time Machine menu and the restore interface appears. You can literally see your windows as they appeared "back in time."
You can use the timeline on the right side of the window to reach a certain point back in time (the timeline shows the times of all backups on your backup drive). If you don’t know exactly when you deleted or changed a file, you can use the back arrow to let Time Machine automatically travel through time to show you when that folder last changed.
Note: Dates in pink indicate the data resides on your Time Machine backup device. Dates in white indicate the data resides on your Mac. In OS X Mountain Lion and Lion, portable Macs have the feature of local snapshots. See this article for details.
You can also perform a Spotlight search in the Time Machine Finder Window search field to find a file. Simply type the Spotlight search field and use the back arrow to have Time Machine search through your backups to find what you are looking for.
Before you restore a file, you can also use Quick Look to preview a file to make sure its the one you want. Highlight the file and press the Space Bar to bring up a quick look.
To restore, select the file/folder and click the "Restore" button. The file will automatically be copied to the desktop or appropriate folder. If the file you are restoring has another file in the same location with the same name, you will be prompted to choose which file to keep or keep both.
Restoring your entire system from a backup
If you are restoring a backup made by a Mac to the same Mac
With your backup drive connected, start up your Mac from the Recovery system (Command-R at startup) or Mac OS X v10.6 installation disc. Then use the "Restore From Time Machine Backup" utility.
Note: If "You can't restore this backup because it was created by a different model of Mac" appears when restoring a backup that was made on a different Mac, follow the onscreen instructions.
If you are restoring a backup made by one Mac to a completely different Mac
Important: If the backup you are about to restore is from a completely different Mac, use the Migration Assistant to transfer data from the backup, as described in the next section.
Migrating a Time Machine backup to a new Mac
When you buy a new Mac, you can transfer all of your applications, files, settings, and other information from a Time Machine backup you've already made.
You will be asked if you want to transfer files when you start up your new Mac for the first time. Or, you can use the Migration Assistant (located in Applications/Utilities).
After Migration Assistant completes the transfer and you select your existing Time Machine backup drive, you will be prompted with "Inherit Backup History". Once selected you will be able to continue to use your existing Time Machine backup on your new Mac.
Backup drive fills up
As your backup drive begins to fill up to its capacity, Time Machine intelligently deletes the oldest backups to make room for newer ones (and will alert you if the "Notify after old backups are deleted" option is selected in Time Machine preferences).
If your backup disk is filling up often causing your oldest available backups to be erased sooner than you might want, consider the following options:
- Use an additional drives for your backups or transfer your backups to a new, larger drive as detailed above. When you connect a new drive for the first time, use Time Machine preferences to select the drive. Tip: You can also browse the original backup drive for past backups by using "Browse other Time Machine Disks"--to see this choice, hold the Option key then click the Time Machine menu in the Finder (to see the menu, "Show Time Machine status in the menu bar" must be selected in Time Machine preferences.
- Reduce the amount of information being backed up by adding to the "Exclude these items from backups" list in Time Machine preferences, as mentioned above. Your backup drive will fill up less often.
- Delete file(s) that are no longer needed (such as from your desktop, Documents folder, or other Home folder locations), so they will no longer be backed up. You can also enter the Time Machine restore interface and find files that can be removed from the backup drive itself to conserve space. To do this, select the file(s) and from the Action pop-up menu (gear icon) in the Time Machine Finder window choose "Delete All Backups of...". Be sure to only delete files you are sure you won't need or want to restore later.