Configure a Destination in Ventura or Later

To set up a Time Machine destination in Ventura or later:

1. Go to System Settings > General > Time Machine.

2. Click Add Backup Disk.

   A dialog appears (Figure 10), listing all local and network volumes eligible to be a destination disk and the amount of free space on each local disk.

   

3. Select a volume and click Set Up Disk. Another dialog (Figure 11) appears.

   

4. Optionally, but strongly recommended, leave Encrypt Backup selected, enter and repeat a password, and enter a hint (see the sidebar About Time Machine Encryption, above). To forgo encryption, turn off Encrypt Backup.

5. For local volumes only, a Disk Usage Limit control also appears. If you’re content with using the entire volume for Time Machine (and, in most cases, that is preferable), leave Disk Usage Limit set to None. However, if you want to use only a portion of the volume for Time Machine and leave extra space for other uses, select Custom and use the slider to specify the maximum amount of space your Time Machine backups can occupy.

6. Click Done.

Normally, Time Machine then runs hourly, but you can change the frequency if hourly backups are too frequent for your needs. To do this, click the Options button in System Settings > General > Time Machine and choose an option from the “Back up frequency” pop-up menu: Manually, Automatically Every Hour (the default), Automatically Every Day, or Automatically Every Week.

Now, skip ahead to About Time Machine’s Scheduled Runs.

Configure a Destination in Monterey or Earlier

To set up a Time Machine destination in Monterey or earlier:

1. Open System Preferences > Time Machine.

2. Click Select Backup Disk.

   A dialog appears (Figure 12), listing all local and network volumes eligible to be a destination disk and the amount of free space on each local disk.

   

3. Select a volume.

4. Optionally, but strongly recommended, select “Encrypt backups” (see the sidebar About Time Machine Encryption, above).

5. Click Use Disk. If you enabled encryption, also enter and repeat a password, enter a hint, and click Encrypt Disk.

6. You can optionally select more than one destination; if you do, Time Machine alternates destinations with each hourly run. To select another destination, click Select Disk, select another disk, and click Use Disk. You’re prompted to choose whether you want to replace the previous backup disk or back up to both disks. Click Use Both. (To add still more destinations, scroll down in the list of destinations and click Add or Remove Backup Disk. If you select more than two destination disks, you won’t be asked again whether you want to replace the existing destination.)

On the Time Machine preference pane, the Back Up Automatically checkbox is selected, and a timer begins a two-minute countdown before your first backup begins. (You may prefer to turn it off until you’ve excluded files from Time Machine, which I discuss shortly.)

About Time Machine’s Scheduled Runs

Time Machine runs hourly by default, unless you changed the frequency in System Settings in Ventura or later (see above) or using a third-party utility; see Modify the Backup Interval.

Your only visible indication that Time Machine is currently backing up files is a subtle change to the Time Machine menu icon: in Catalina and earlier, a little triangle appears at the bottom of the icon , while in Big Sur or later you get a pair of chasing arrows . The menu displays more information about the current backup status.

During each of Time Machine’s runs, it backs up only the files that have changed since its previous run (except files you’ve excluded, as I discuss next). If an app stores its data as a package (a folder that looks like a file in the Finder), Time Machine backs up only changed items within the package. (Among many other apps, Keynote, GarageBand, and DEVONthink use packages for their data.)

How to Exclude Items

To make sure an item doesn’t get backed up:

1. Open System Settings > General > Time Machine (Ventura or later) or System Preferences > Time Machine (Monterey or earlier).

2. Click Options and, in the dialog that appears, do one of the following:

   • Click the plus button, navigate to the item you want to exclude, select it, and click Exclude.

   • Drag any item (a file, folder, or volume) from the Finder into the list of excluded items in the dialog.

3. Click Done (Ventura or later) or Save (Monterey or earlier).

Unfortunately, Time Machine offers no way to automatically exclude files that meet certain criteria, regardless of their location—for example, all files over 2 GB or all disk images. The only way to automatically exclude a set of files whose members may change over time is to exclude the folder that contains them. However, see the sidebar Using Smart Folders for Exclusions, just ahead.

If you use multiple destination disks for Time Machine, bear in mind that whatever you exclude from Time Machine will be omitted from all Time Machine backup disks.

If you later want to stop excluding something from Time Machine, repeat these instructions, but in step 2 select the item and click the minus button.

Items to Consider Excluding

If you’re using only Time Machine for backups—and in particular if you don’t also have a full duplicate (bootable or otherwise)—then you shouldn’t exclude anything, because Time Machine can only restore what it backed up. However, if you do have a duplicate, you can save space and improve Time Machine’s performance by excluding certain items, such as these:

• Virtual machine disk images: Apps that let you run Windows (or other operating systems) on your Mac typically store your entire virtual machine installation in a special disk image file. These files can reach tens of gigabytes, and since they change every time you run the virtual machine, Time Machine attempts to back them up with each run. That’s not so much of a problem when Time Machine uses an APFS-formatted destination, as that enables it to copy on the portions of files that changed, but on Mac OS Extended destinations, this process can bog down your Mac and waste space on your backup disk. In that situation, I suggest excluding them from Time Machine and backing them up separately—except note the following:

  • Parallels Desktop lets you disable Time Machine backups for all your virtual machines without using the Time Machine preference pane. (With a virtual machine running, go to Actions > Configure > Backup and select “Do not back up with Time Machine.”) Alternatively, you can select SmartGuard in the same window to enable automatic snapshots, which reduce the amount of data a backup app must copy on each run; you can make Time Machine even more efficient when backing up these snapshots, by clicking Details and then selecting Optimize for Time Machine.

  • VMware Fusion by default stores disk images in ~/Documents/Virtual Machines, with the extension .vmwarevm. Technically, the file with the .vmwarevm extension is a package (again, a special folder that looks and acts like a file); the actual disk image file inside the package has an extension of .vmdk. But it’s easiest to exclude the entire .vmwarevm file.

  • VirtualBox keeps its disk images in ~/Library/VirtualBox/VDI with an extension of .vdi.

• Certain other large disk images: Disk images (typically with the extension .dmg or .sparseimage) serve many useful purposes, such as providing a convenient way to package and distribute downloadable software. You can also create your own disk image using Disk Utility, optionally encrypting it so that all the files within are protected with a password. However, most disk images that you may have created yourself, for whatever reason, have the same defect as virtual machine disk images: every time any file inside changes, the whole file changes, forcing Time Machine to back up the entire image again. That’s not a big deal if the image is small, but if it’s in the range of hundreds of megabytes or larger, it will cause problems with Time Machine. So, you might want to add such files to the list of items to be excluded and back them up in a different way (for example, as part of a duplicate).

Beyond the items just listed, you might in some cases want to consider excluding the following:

• System files: As noted earlier, Time Machine automatically excludes the signed system volume in Big Sur and later; however, in Catalina and earlier the files that make up macOS—the contents of your /System and /Library folders, various invisible files and folders at the main level of your disk, and the apps included with macOS, such as Mail and Safari—are all included by default in a Time Machine backup. If you’re running out of space on your backup disk and you already have a bootable duplicate or two (see Create and Use a Duplicate), you could exclude the system files to save space.

  To exclude the system files, add the folder /System to the list of items to be excluded. The alert shown in Figure 13 appears; click Exclude All System Files.

  

• Other local volumes: Time Machine doesn’t back up other network volumes mounted on your Mac; however, it normally does back up other local volumes, including external USB and Thunderbolt drives and additional internal drives. If the data on any of these volumes isn’t particularly valuable—for example, disks mainly used as scratch space for Photoshop—you can save a significant amount of space on your backup disk by adding them to the list of items to be excluded. In addition, if the drive containing your bootable duplicate is connected to your Mac, you should tell Time Machine to avoid backing up that volume; it already is a backup, so backing it up again wouldn’t be particularly helpful, and it would massively increase the amount of storage space and time that Time Machine needs.

• Downloads: Your ~/Downloads folder may contain a number of large files that disappear quickly (because you delete them after you install software or relocate the files to other folders). If so, exclude that folder.

• Video: If you download movies or TV shows regularly and then delete them right after you watch them, you can save tons of space on your backup drive by excluding the folder containing those files (typically ~/Music/iTunes/iTunes Media/Movies and ~/Music/iTunes/iTunes Media/TV Shows). But do this only if you’re sure you can download the movies again if necessary. (Movies and TV shows purchased from the iTunes Store, for example, can be downloaded again for free as long as they’re still in Apple’s catalog.)

Prevent or Force Time Machine Backups

Sometimes you may want Time Machine not to run, even though its destination disk is connected. You may, for example, want to make sure every last bit of your computer’s CPU and disk speed is available to devote to some important task, or you may want to keep a noisy external drive quiet for part of the day. Any time you want to suspend Time Machine from running backups, you can. In Ventura or later, go to System Settings > General > Time Machine, click Options, and choose Manually from the “Back up frequency” pop-up menu; in Monterey or earlier, open the Time Machine preference pane and deselect Back Up Automatically. Time Machine remembers all its settings, and resumes backups whenever you reselect it.

On the other hand, in some situations you may want to make sure Time Machine immediately backs up your files. For example, you may have recently saved or downloaded an important document, but the next scheduled Time Machine run isn’t for another 45 minutes. To force an immediate backup, even if Time Machine is off, choose Back Up Now from the Time Machine menu or right-click (or Control-click) the Time Machine icon in the Dock and choose Back Up Now from the contextual menu. (To immediately stop a backup in progress, choose Stop Backing Up from Time Machine’s Dock menu or Skip This Backup from the Time Machine or menu.) Note that this doesn’t work with local snapshots (again, see the sidebar Local Snapshots); it applies only when your regular Time Machine volume is available.

Regardless of how regularly Time Machine runs, the way it purges older backups can, in some cases, delete files you thought were backed up; read the sidebar The Time Machine Schedule Problem, next. If you want to alter the frequency of Time Machine’s regular backups to something other than hourly, see Modify the Backup Interval, just ahead.

Modify the Backup Interval

Time Machine normally runs every hour, though starting in Ventura you can change that interval to daily or weekly; see Configure a Destination in Ventura or Later. But what if you’re running an earlier version of macOS, or you’d like Time Machine to run every three hours or twelve hours? You can adjust the backup interval using a free utility. TimeMachineEditor lets you set Time Machine’s backup interval to any number of hours and choose arbitrary recurring backup times (such as hourly on Mondays and Fridays, or every Saturday and Thursday at 6:15 A.M.). And you can opt to have backups run automatically when the Time Machine disk is mounted, when your Mac wakes up, or both. One oddity is that TimeMachineEditor automatically deselects the Back Up Automatically checkbox on the Time Machine preference pane in Monterey and earlier. But don’t worry about this, because that checkbox (or switch) affects only Time Machine’s default hourly backups.

Restore Files and Folders in the Finder

If you notice that a file or folder is missing, or that you’ve accidentally changed it and need an older version, follow these steps to retrieve an item from your Time Machine backup:

1. In the Finder, make sure the window that contains the item you want to restore (or the one that used to contain it, if it’s been deleted) is frontmost. You can do this by clicking anywhere in the window. (Not certain where the missing item was stored? Skip ahead to Restore Files and Folders Using Spotlight.)

2. Click the Time Machine icon in the Dock or choose Enter Time Machine from the Time Machine menu.

   The frontmost window moves to the center of the screen, the background blurs, and additional copies of the window recede into the background in a 3D “time warp” display (Figure 14). In this book, I refer to this view as the Time Machine screen.

   

3. To locate the file or folder you want, do one of the following:

   • To the right of the stacked windows, click the top arrow (for “back in time”). Time Machine zooms back to the most recent backup in which that window’s contents were different. Keep clicking to continue zooming back through previous versions of that window. Click the bottom arrow to move forward in time.

   • Use the controls along the right edge of the screen to jump to a particular backup. As you hover your pointer over the small horizontal lines, they zoom in to display the date and (for recent backups) time of each backup. Click a line to jump right to that version of the window. (If you’ve only just set up Time Machine, you won’t see many dates here.) As you zoom backward or forward in time, the date and time of the backup you’re currently viewing is shown at the right between the arrow buttons.

4. If you’re unsure whether a file is the one you want, click once to select it and press the Space bar to activate Quick Look, which gives you a live, full-size preview of the file. To close the Quick Look window, click the X icon in the upper-left corner.

5. Once you’ve selected the item you want to restore, decide whether you want to restore it to its original location or somewhere else:

   • To restore to the original location, click the Restore button. Time Machine immediately restores the selected item, and returns you to the Finder. (Time Machine may prompt you to enter an administrator password for certain items.)

     You can use this procedure even if you want to restore an older version of a file but keep the current version. After you click Restore and the Finder reappears, you’ll see an alert asking whether you want to replace the existing file, keep both copies (in which case the one already in that location is renamed with “(original)” at the end), or keep the original (thus canceling the restoration).

   • To restore to a different location from the original, right-click (or Control-click) the item and choose “Restore ‘filename’ to” from the contextual menu, navigate to the desired destination, and click Choose.

   If you decide against restoring any files, instead click the Cancel button or press Esc (Escape).

Restore Files and Folders Using Spotlight

Although you can, on the Time Machine screen, navigate around your Mac manually, you could spend a lot of time searching for a file at different times in different locations on your disk if you don’t know where it is. No worries: Spotlight to the rescue!

If you know something about a missing file or folder, such as a word in its title or its contents, you can use Spotlight to find it within your Time Machine backups. Follow these steps:

1. Click the Time Machine icon in the Dock or choose Enter Time Machine from the Time Machine menu. The Time Machine screen appears.

2. Type something in the Spotlight search field in the toolbar of the window, optionally specifying additional search criteria.

3. Using the back and forward arrows or the controls on the right of the screen, navigate to an earlier point in time. Each time you move to another backup, the Spotlight window changes to reflect the results of the search at the time that backup was performed.

4. When you find the desired file, select it and click Restore. Time Machine copies it to its original location. To restore to a different location, right-click (or Control-click) the item and choose “Restore ‘filename’ to” from the contextual menu, navigate to the new location, and click Choose.

Restore Data Within Apps

When Time Machine was first introduced, Apple made a big deal about how it could restore not only entire files in the Finder but also individual items within apps, such as pictures in iPhoto, contacts in Address Book (later renamed Contacts), and messages in Mail. GarageBand 4 through 6 (a.k.a. GarageBand ’08 through GarageBand ’11) could also restore projects from within the app using Time Machine. But Apple dropped in-app Time Machine support from GarageBand 10 and iPhoto ’11 (version 9.2 and later), and never included it in Photos (which replaced iPhoto). That left Contacts and Mail as the only apps with built-in Time Machine support, and even those two apps lost Time Machine integration in Big Sur. So the instructions I provide here are only for those running Catalina or earlier, and only for Contacts and Mail.

Switch to Another Time Machine Backup

If you’re backing up just one Mac to just one Time Machine disk, you can skip this section. But if you’re backing up multiple Macs or backing up to more than one destination disk, you may need a way to tell Time Machine to show you a different set of backups from the one you’re currently using, in order to restore (or delete) items from it. (You might also need to use this procedure to see backups from your existing Mac if you’ve recently restored your entire disk from a Time Machine backup, if you’ve changed its name in System Settings > General > Sharing or System Preferences > Sharing, or if your logic board has been replaced.)

To browse other Time Machine backups:

1. Make sure the volume with the backups you want to view is mounted in the Finder.

2. Right-click (or Control-click) the Time Machine icon in the Dock and choose Browse Other Time Machine Disks from the contextual menu, or Option-click the Time Machine icon in your menu bar and choose Browse Other Backup Disks from the contextual menu.

3. In the window that appears, select the backup you want to use and click Use Selected Disk. The Time Machine screen appears.

You can now recover or delete items in the usual way.

Restore Your Startup Volume Using Time Machine

If a major disk crash or other catastrophe requires you to restore your entire startup volume rather than merely individual files or folders, you can do so with Time Machine, by way of recovery mode:

1. Make sure the drive containing your Time Machine backup is available:

   • If you back up directly to an external drive, plug it in.

   • If you back up over a network to a drive connected to another Mac using Time Machine Server (see Use a Mac as a Time Machine Server), make sure that the server Mac is turned on and that both Macs are connected to the same network.

   • If you back up to a NAS, I suggest connecting to it with an Ethernet cable (if your Mac has an Ethernet port or adapter) rather than using Wi-Fi, as that will speed up the restoration. In addition, anecdotal evidence suggests that you’ll get better performance if, after connecting the Ethernet cable, you turn off your Mac’s Wi-Fi for the duration of the process.

2. Restart your Mac in recovery mode (see Something Recovery Something).

3. Select Restore from Time Machine Backup and click Continue. Read the instructions, then click Continue again.

4. Select your Time Machine backup disk. If the disk was encrypted, enter its password when prompted. (If you selected a network destination, click Connect. You may be prompted to enter its disk password; do so, and click Connect again. Then select the volume you want to restore.) Click Continue once more.

5. If the Time Machine disk contains backups for more than one volume, select the one you want from the Restore From pop-up menu. Then select the particular backup you want to restore—likely the most recent one (the first one in the list). Click Continue.

6. On the Select a Destination screen, select your internal disk. Click Restore. If prompted, confirm that you want to restore your data.

Time Machine restores your data. When it finishes, follow the instructions to restart your Mac.

Restore an External Disk with Time Machine

Let’s say you’re using Time Machine to back up an external disk, but that drive dies, and you need to restore its data. The ordinary way of using Time Machine won’t work, because you’d need to navigate to the location where the data is missing—but you can’t, since that drive doesn’t work! What can you do?

One way to solve the problem is to obtain a replacement drive and give it the same format and name as the old drive. Then, open a window on that drive and click the Time Machine Dock icon (or choose Enter Time Machine from the Time Machine menu). Navigate to the most recent backup and select all the top-level items. To restore the data, right-click (or Control-click), choose “Restore # Items to” from the contextual menu, and select the new drive. Once the data has been restored, follow the instructions in Restarting Time Machine Backups After a Restore to associate the new drive with the old backup.

If that doesn’t work for any reason—or if you have to restore the data to a different location—the path of least resistance is to Restore Files Without Time Machine.

Restore Files Without Time Machine

If you ever need to restore files and Time Machine isn’t working for some reason, you can browse the contents of your Time Machine disk in the Finder and then drag any file to your desktop (or another folder) to copy it to your main disk. (You should always avoid opening files directly on your backup disk.) But be aware that Time Machine stores files on your backup disk in one of three different ways:

• When you connect a Mac OS Extended Time Machine drive directly to your Mac, Time Machine stores backups for your computer in a folder like this:

  volume name/Backups.backupdb/computer name

  Inside that folder, you’ll find a timestamped folder for each individual backup Time Machine is currently storing. (There’s also an alias named Latest that, when opened, shows you the latest backup.)

• By contrast, when Time Machine backs up a Mac over a network, it puts a sparse bundle disk image at the top level of the volume whose name is similar to your computer’s name, as in:

  volume name/MacBook_Pro.sparseimage

  If you double-click that disk image to mount it in the Finder, you’ll see the list of folders with each stored Time Machine backup.

• On a locally connected drive formatted as APFS, Time Machine stores snapshots (which look like disks with the Time Machine icon) at the top level of the disk. If you’re backing up multiple Macs to a single APFS disk, Time Machine creates a separate volume for each one (within the same APFS container), mounting each in the Finder. You can browse through the contents of the snapshots, which reflect the exact hierarchy of your disk, just as you would any other disk or folder.

Check for Hidden Exclusions

If a file or folder that you believe should be backed up is not appearing on the Time Machine screen (see Restore Data with Time Machine), first check to see that the item in question isn’t on the Exclude list (see Exclude Files from Time Machine).

Note, however, that under certain circumstances, Time Machine can exclude files and folders without showing them on the Exclude list! To check the inclusion/exclusion status of a file or folder, follow these steps:

1. Open Terminal (in /Applications/Utilities).

2. Type tmutil isexcluded followed by a space (but don’t press Return yet).

3. From the Finder, drag the file or folder you’re wondering about into the Terminal window. This puts the full path to that item on the same line, right after the command you just entered.

4. Press Return.

The next line will start with either [included] or [excluded], indicating whether the item is included in your Time Machine backups or not. If an item is excluded and you want it to be included, type tmutil removeexclusion followed by a space. Drag the item into the Terminal window, and press Return.

Restore Files After a Hardware or Name Change

Because of the way Time Machine stores its data, certain changes to your system could cause Time Machine to “lose” its backups—to seemingly forget which backups go with your disk, such that no existing backups appear when you visit the Time Machine screen, and your next backup starts over from scratch.

Among the changes that could trigger this condition are:

• Restoring your entire disk (not just a few files or folders) from a Time Machine backup

• Having your logic board replaced

• Changing your Mac’s name in System Settings > General > Sharing (Ventura or later) or System Preferences > Sharing (Monterey or earlier)

In these cases, you can retrieve files from that previous set of backups and even reconnect Time Machine to your current disk. See the sidebar Restarting Time Machine Backups After a Restore, earlier, for details.

See What Time Machine Is Really Up To

To find out how much data (number of files or size) Time Machine backs up with each run, get details on any errors it encounters, or find clues to solving random problems, open Console (in /Applications/Utilities). Make sure the list of available logs is visible on the left (if not, choose View > Show Sources) and select system.log in the list under Reports. Then type backupd in the Search (or Filter) field to display only the entries involving Time Machine.

If you notice that Time Machine is regularly backing up much more data than what should have changed in the past hour, first follow the suggestions in this section and in Items to Consider Excluding. Then look for other especially large files that may be causing problems.

One easy way to find such files is to use BackupLoupe, which lists every snapshot that your Time Machine volume currently holds. Select any snapshot in the list and the app displays only the files and folders that were copied during that particular run, along with their sizes.

If you want even more detail about what Time Machine is doing, you can try Back-In-Time. This utility comes from Tri-Edre, the same company that makes the app Tri-BACKUP. When I first saw Back-In-Time, I was confused because I thought it did nothing more than show me the same files as on the Time Machine screen, but with a different interface. In fact, it lets you dig deeply into your Time Machine backups to see information that would be difficult to learn in any other way. You can:

• See at a glance how many copies of each file Time Machine is storing

• See at exactly which point in time a file appeared in, or was deleted from, a certain folder

• List all the files copied during a certain backup run

• Compare any two snapshots (in part or whole) to see what’s different between them, and even two versions of the same file to see what’s changed

You can also restore files or delete data from Time Machine—with more flexibility than Apple’s interface offers—directly in Back-In-Time.