We've written before about backing up an iPhone. This one is about the Mac — and it's the tip we most wish everybody had already acted on, because it's the difference between a bad day and a genuinely awful one.
Macs are reliable. They're also dropped, spilled on, stolen, and occasionally they simply stop. And the thing that hurts in every one of those cases isn't the machine — it's the photos, the letters, the tax folder, the thirty years of things you assumed were somewhere safe.
The good news is that your Mac already has a complete backup system built in. It's called Time Machine, it's free, and it needs one thing you may well already own: an external drive.
What Time Machine actually does
Once it's set up, Time Machine quietly copies everything on your Mac to that drive, over and over, in the background. You don't have to remember to do anything.
It keeps a history, not just a copy. That's the part people don't expect:
- The whole Mac, recoverable. If the machine is lost or replaced, a new Mac can be set up from the backup and come back looking exactly as it did — apps, files, settings, desktop picture and all.
- One file, brought back from last Tuesday. Deleted something, or saved over a document and wished you hadn't? You can go back and pull out the earlier version, leaving everything else alone.
- Automatic. It runs on its own as long as the drive is connected.
The thing to be clear about: iCloud is not a backup
This is the most common misunderstanding we meet, and it's an easy one to fall into, because iCloud genuinely is doing something useful.
iCloud syncs. It keeps the same files looking the same on all your devices. So if you delete a photo on your iPhone, iCloud faithfully deletes it from your Mac too — that is it working correctly, and it is exactly what you don't want when the deletion was a mistake.
A backup is different: it's a separate copy that doesn't change just because the original did. Keep using iCloud. Just don't count it as your backup.
What you need
- An external drive that plugs into your Mac — a portable USB or Thunderbolt drive is perfect, and they're inexpensive now.
- Or, if there's more than one Mac in the house, a NAS — short for network-attached storage. It's a small box with a drive inside that plugs into your internet router, and Time Machine backs up to it over your home network. Every Mac in the house backs up to the same box on its own, with nothing to plug in, including laptops whenever they're home on the Wi-Fi. The one we usually recommend is the Buffalo LinkStation 710: it supports Time Machine, and it comes with its drive already installed, in a choice of sizes. Pick one large enough for every Mac in the house.
- Ideally, at least twice the storage of your Mac — or of all your Macs added together, for a NAS. More room means a longer history before Time Machine starts letting go of the oldest backups.
- If you're using an external drive, one you're happy to erase. Setting it up wipes whatever is on it, so don't use one that's already holding the only copy of something.
A few things to know if you're choosing a NAS:
- It costs more than a single drive, and it needs setting up, including a space prepared for each Mac's backups.
- It has to support Time Machine. The Buffalo does; other makers such as Synology and QNAP have models that do too — but check before you buy.
- Backups over Wi-Fi are slower than a drive plugged straight in, especially the first one. After that it only copies what has changed.
- It still lives in the same house as your Macs, so the advice under One more copy, if you can below still applies.
Once a NAS is ready, each Mac is set up exactly as below: it simply appears as a choice when you click Add Backup Disk.
If you'd rather we just told you which drive to buy, or set up a NAS for the whole house, ask — it's a short answer, and it depends mostly on how much is on your Macs.
How to set it up
- Plug the drive into the Mac. If it asks whether you'd like to use it with Time Machine, you can say yes and skip ahead.
- Open System Settings from the Apple menu at the top left, then General → Time Machine. (On an older Mac it's System Preferences → Time Machine.)
- Click Add Backup Disk — or the + button — and choose your drive from the list.
- Leave Encrypt Backup switched on and give it a password. This matters: an unencrypted backup drive is a complete copy of your life that anyone who picks it up can read. Keep that password somewhere you'll still have it if the Mac is gone — without it the backup cannot be opened, and there is no way around that.
- Click Set Up Disk. The Mac will warn you that the drive will be erased. That's expected.
Then leave it alone and let it work. The first backup is the big one, because it copies everything you have — start it at a point when you don't need the Mac, and leave the drive plugged in until it finishes on its own. Everything after that is much smaller, because it only copies what has changed.
Getting something back
One file or folder: open the folder where it used to live, then choose Enter Time Machine from the Time Machine icon in the menu bar. You can travel back through earlier versions of that same folder, find the file as it was, and click Restore.
The whole Mac: when setting up a new or repaired Mac, choose to transfer from a Time Machine backup when it asks. Everything comes across.
Keeping it honest
A backup you've stopped checking is a backup you're only assuming you have. Two small habits:
- Glance at it now and then. The Time Machine screen tells you when the last backup happened. If that date has gone stale, something needs looking at — usually the drive has been unplugged since.
- If you leave the drive plugged in permanently, good. If you only connect it occasionally, put it somewhere you'll trip over it — a backup that lives in a drawer backs up nothing.
One more copy, if you can
An external drive sitting next to the Mac protects you from almost everything — except the fire, flood or burglary that takes both. If your Mac holds things that could never be replaced, it's worth having a second copy somewhere else: a paid online backup service, or simply a second drive you keep at the office or a relative's house and swap over now and again.