Time Machine

Time Machine is the built-in backup that works with your Mac and an external drive (sold separately) or Time Capsule. Connect the drive, assign it to Time Machine, and start enjoying some peace of mind. Time Machine automatically backs up your entire Mac, including system files, applications, accounts, preferences, 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.

OS X Lion lets you encrypt the Time Machine backup external drive using FileVault 2.


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. You can also use a secondary internal drive if your desktop Mac has one (that is, a drive that you don't start up from).

If you haven't specified a Time Machine backup device yet, the first time you connect an external drive, Time Machine asks if you would like to use it as a Backup Disk.

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.

On OS X Lion, check "Encrypt Backup Disk" if you want to encrypt the Time Machine backup external drive using FileVault 2.

That's all you have to do for Time Machine to automatically backup your Mac. 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.


About the first backup to an external drive
The first backup may take a while. You may want to set up Time Machine in the evening so that the initial backup can be done overnight. 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 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.


Changing your backup drive
You can manually select another backup drive in Time Machine preferences.

1. Select Time Machine menu > Open Time Machine Preferences…
2. Click "Select Disk…"
3. Choose a drive where backups will be stored, then click “Use Backup Disk”

Note: 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 backup to an external drive that's connected to an AirPort Extreme, Time Capsule, 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) or Apple Partition Map (APM) partition types are 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 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 partition of the Time Machine backup to start from. Once booted, you will have all of the functionality of the OS X Lion recovery partition.


Setting up Time Machine for backups using a Time Capsule
If you have a Time Capsule on your home network, you can use it as your Time Machine backup device. See the documentation that came with your Time Capsule for information about setting it up on your home network.

Once your Time Capsule has been configured for your home network, open Time Machine preferences and click "Select Disk…".

From the sheet that appears, select the 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 Time Capsule. Enter the name and password or password only that you set for your Time Capsule via the Airport Utility.

About the first backup to a Time Capsule
The initial backup may be faster if you leave your computer in the same room as the Time Capsule, or use an Ethernet cable to connect your Mac to one of the Ethernet ports on the Time Capsule.  You should not interrupt the initial backup. You can continue to use your Mac while Time Machine backs up. For more information, see Backing up with Time Capsule for the first time.
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.


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 the 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. 

The "Lock documents…after last edit" setting is the time that an idle file will lock in versions.


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."

If prompted, enter an administrator name and password to proceed with the restore.


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 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
With your backup drive connected, start up your Mac from the Lion recovery partition (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
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).

If you use a Time Capsule, see Restoring files from a Time Capsule backup.

Once 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:

1. 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.
2. 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.
3. 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.