How to Backup Your Mac

The Complete Guide to Mac Backup.

You have valuable data residing on your computer

From irreplaceable family photos to the presentation you're working on, they all need to be protected. Without a proper backup system in place, though, you could lose all of those digital files in a blink of an eye.

But don't worry; backing up your Mac is so surprisingly simple, you only have to set it up once to enjoy the peace of mind that all your files are safe. Here's how to back up your computer in OS X using Time Machine and other utilities.  

In this guide, you'll learn to automatically back up versions of your most important files to another drive and also create a complete copy of your entire system.

This way, in the event of a computer crash, virus, accidentally deleted file, or another common tech catastrophe, you can get back up and running in no time.

Note that the steps below will back up your data locally, but you also need offsite/online backups to completely safeguard your files. Local backups to an external hard drive or another computer on your network won't help if a thief steals your computer and external drive or a fire or natural disaster destroy everything in your house. I've even seen cases where both the computer and the backup hard drive both failed at the same time. (Murphy's Law seems to apply particularly often when it comes to computers!)

I found this unwelcoming screen today when I opened OS X’s Disk Utility. Yikes, time for backup!

How to Back Up Your Computer with Time Machine

Mac OS X (10.5 and above) has an excellent built-in backup tool called Time Machine. Once you plug in a hard drive and set up Time Machine, it will work automatically in the background, continuously saving copies of all your files, applications, and system files (i.e., most everything except for the stuff you likely don’t need to back up, such as files in the trash bin, cache files, and log files). If you run out of disk space, Time Machine will automatically erase the oldest version of the files to make way for the new ones.

It's pretty much a set-and-forget system for local backups:


Connect an external hard drive to your Mac

You'll need a drive that is at least the same size as your Mac's internal drive. With storage quite cheap these days, aim to use a drive that's two to four times the size of the drive you're backing up. Plug in your external hard drive (via USB, FireWire, or Thunderbolt, depending on your drive). You can also use Time Machine with an external hard drive connected to an Airport Extreme router, with an AirPort Time Capsule network device, or with other network drives. (For simplicity's sake, we're using an external drive for the examples below. Directly connected external drives are also faster.)  

Tip: Time Machine will by default use up all the space available on the drive. If you'd also like to use some of the hard drive space for storing other files, you'll need to partition the drive into two volumes: one for the Time Machine backups and one for your other files. You can do that with OS X's Disk Utility found under Applications > Utilities. MakeUseOf has detailed instructions for doing this, which comes in handy if you don't want Time Machine taking over your entire 4TB drive.  

Turn on Time Machine and select the backup destination

Once your external drive is plugged in, go to System Preferences > Time Machine and toggle the switch from "Off" to "On."

Then click the "Select Disk…" button to select the drive or volume you want to use for Time Machine. Time Machine will ask you if you want to use the disk as your backup destination and will give you the option to encrypt the backups with a password.

The drive needs to be formatted as Mac OS X Extended (Journaled); if it's not, Time Machine will prompt you to reformat the drive (which will erase all files on it!).


(Optional): Exclude items or get notified of old backup deletions

The "Options" button in Time Machine will let you exclude volumes from the backups or get notifications when old backups are deleted.


Let Time Machine do its work

Those options selected, backups will happen automatically every hour. Time Machine keeps:

  • Hourly backups for the past 24 hours
  • Daily backups for the past month
  • Weekly backups for all previous months

How to Restore Files from Time Machine Backups

To view and restore files or folders from Time Machine, go to the Spotlight search and enter "Time Machine" to switch to the Time Machine view.

Here you'll be able to scroll through the timeline on the right site to go back to a certain point in time or search for a file. With a file highlighted, press the space bar to get a quick look of it or click the "Restore" button to copy the file back to the appropriate folder. (In case of filename conflicts, you'll be asked which file to keep or whether to keep both versions.)  

Time Machine can also restore your entire system at once, using the latest copies of all your files. While your Mac is restarting, hold down the Command (⌘) and R keys, and release the keys when the Apple logo appears. Then select "Restore from a Time Machine Backup."

You can't really rely on Time Machine for a complete full-system backup, however, if your startup disk is damaged and you can't boot into your Mac. For times like these, you'll need to have a clone (or complete image) of your system.

How to Create a Bootable Backup of Your Mac

A clone is an exact duplicate of your entire system. With a bootable clone of your drive, you can boot from your backup in minutes and keep working even if your Mac is having startup problems.

OS X's built-in Disk Utility can create cloned images of your drive, but third party utilities such as SuperDuper! ($28) And Carbon Copy Cloner ($40) are generally better and lots easier for the job, because you can schedule the backups and access more features and options. We want to make sure backing up is as automatic and as easy as possible, so either program is well worth the investment. Both cloning apps have plenty of fans, so it's really a matter of preference here; both SuperDuper! And Carbon Copy Cloner offer free trials so you can figure out which one you prefer. The examples below use SuperDuper! screenshots. Here's how to create your bootable, complete backup


Open the cloning tool and choose your source and destination volumes

After installing and launching the cloning app, you'll need to choose where to store the backup. In the left drop-down menu, choose your Mac volume to back up. Then choose the destination volume in the right drop-down menu.

You can back up to an external drive, networked computer, or an image file (which you can store on a network volume or locally). As with using Time Machine, the drive should be formatted as Mac OS Extended (Journaled) for best compatibility with OS X. (If yours is formatted as a FAT32 Windows volume, you should erase and reformat the drive using Disk Utility.)

You can even store both your Time Machine and cloned images on the same drive, but it's best to first partition the drive into two volumes, one for each purpose so that both can manage their allotted backup space. Personally, I prefer to have both on separate drives, to avoid having all the backups in the same basket.


Select the backup script

SuperDuper! offers a few built in backup scripts for backing up all files or just your user files.

Choose "Backup-all files" for your complete and bootable backup of your system. ("Backup-user files" doesn't create a bootable backup. Rather, it backs up just the Home directories of the accounts on your computer.)


(Optional): Choose your options

If you click the "Options…" button, you'll be able to specify whether you want the computer to repair permissions for your files before cloning them (leave unchecked by default) and what you want the program to do during the copy process. "Erase Backup, then copy files from Macintosh HD" is the default option--and the only one available for unregistered versions of SuperDuper! This will erase the destination volume at the start to ensure the result is an exact copy. The other options let you do incremental backups which will save you time


Schedule your backups

You could just hit the "Copy Now" button to create your clone, but, again, because we want to set up automated backups, we'll hit the "Schedule…" button instead. In the scheduling screen, you tell the app when you want the backups to run.


Let the cloning begin

After reviewing your choices, click "OK" and you're done. The program will automatically make bootable copies of your Mac on the schedule you chose, deleting older backups on the same drive if you run out of space.

Congrats on setting up your automatic backups!