How to Back Up Your Computer: A Simple Plan That Works

01Quick answer

To back up your computer in a way that actually protects you, keep two separate copies of your important files in two different places: one automatic backup to an external drive, and one in cloud storage or on a second drive kept elsewhere. Windows includes Windows Backup and File History; Macs include Time Machine. Set them up once, check they run, and test a restore. This guide is for everyday users who want a simple, reliable routine before something goes wrong.

Diagram

A simple backup plan

1. Original filesDocuments and photos on your computer.
2. Copy oneAn automatic backup to an external drive you keep at home.
3. Copy twoA cloud backup or a second drive kept somewhere else.

02Before you start

• Decide what matters. Documents, photos, videos, music, desktop files, browser bookmarks and anything you created yourself. Apps can usually be reinstalled; your own files can’t.
• Choose an external drive with comfortably more space than your files. A drive used only for backups is best.
• Check your cloud storage space if you plan to use it. Free plans may not be large enough for photos and videos.
• Keep the laptop plugged in during the first backup.

03Why this happens

People usually discover they need a backup at the worst moment. Common reasons files get lost:

Usually simple to fix: (as long as a backup exists)

• A file was deleted or overwritten by mistake.
• A laptop was lost, stolen or dropped.
• An update or reset removed something unexpectedly.
• A drink was spilled on the computer.

Needs the manufacturer or a repair service:

• The computer won’t start and the files aren’t backed up. A qualified data recovery or repair service may be able to help, but success isn’t certain.
• The drive is failing and showing errors.

04Set up a backup on Windows

1. Try Windows Backup. On Windows 11 and recent versions of Windows 10, open the Windows Backup app from the Start menu. It can back up folders, settings and apps to your Microsoft account’s OneDrive storage. Microsoft’s support page explains what is included.
2. Add an external drive copy with File History. Connect your external drive. Search the Start menu for File History (it opens in Control Panel), select your drive and turn it on. File History keeps copies of files in your user folders and saves earlier versions on a schedule.

   What you should see: File History shows the drive and the time of the last backup. Leave the drive connected for the first backup to finish.

3. Check what is included. Make sure folders where you keep important files are covered, including anything outside your Documents or Pictures folders.
4. Plug the drive in regularly if it isn’t always connected, so backups stay current.

05Set up a backup on a Mac

1. Connect your external drive. macOS may ask whether you want to use it with Time Machine. If not, open System Settings, General, Time Machine.
2. Add the drive as a backup disk. Choose whether to encrypt the backup; encryption protects your files if the drive is lost. Write the password somewhere safe.
3. Let the first backup finish. Time Machine then makes regular backups automatically while the drive is connected.
4. Add a second copy with iCloud Drive or another cloud service, or a second drive you store away from home.

06Add a second copy and test it

Choose where the second copy lives

One backup is good; two in different places is much safer, because a single event like a burst pipe, a fire or a burglary can affect everything in one room.

• Cloud storage: OneDrive, iCloud Drive and similar services keep a copy away from home automatically. Check your storage plan is large enough, especially for photos and videos.
• A second external drive: back up to it every so often, then keep it at a relative’s home, at work or somewhere else safe.
• Whichever you choose, protect the account or drive with a strong password and, where offered, two-step sign-in.

Test a restore

1. Pick a non-critical file, make a copy of it on your desktop, then delete the copy.
2. Restore it using File History (Windows) or Time Machine (Mac).

   Did it come back? If yes, your backup works. If not, check the settings and the drive before relying on it.

3. Repeat a test like this every few months.

07Common mistakes to avoid

• Keeping the only backup drive in the laptop bag with the laptop.
• Copying files once and never again. Backups need to be automatic and current.
• Assuming cloud syncing is the same as a backup. If you delete a synced file, it may disappear everywhere.
• Never testing a restore.
• Forgetting the password for an encrypted backup.

08If it still doesn’t work

If File History or Time Machine won’t see your drive, try another cable or port, and check the drive works in File Explorer or Finder. If the drive shows errors, replace it and start a fresh backup. If your computer has already stopped starting, see our guide to a laptop that won’t turn on before trying recovery options. When you retire an old drive or computer, the EPA’s electronics recycling page explains responsible options; erase or keep the drive securely first.

A full backup drive is a good moment to review what you keep; our guide to freeing up disk space helps with the computer side. Back up before major updates too; see our Windows Update guide.

09The short version

Keep two copies of your important files in two places: an automatic backup to an external drive with File History or Time Machine, and a cloud or off-site copy. Check they run and test a restore now and then.

10FAQ

How often should I back up my computer?

Automatic backups handle this for you. File History and Time Machine back up regularly while the drive is connected. If you connect the drive only occasionally, plug it in at least weekly, or after adding important files.

Is OneDrive or iCloud enough as a backup?

Cloud storage is a good second copy, especially for photos and documents. Because syncing mirrors deletions, keep an external drive backup too, so a mistake on the computer can’t remove every copy.

Do I need to back up apps?

Usually not. Apps can be reinstalled from their official stores or websites. Focus on your own files, and note down licence details for software you paid for.

What size external drive do I need?

Choose one comfortably larger than the files you want to back up, so there’s room for older versions as well. Check how much space your files use in Settings or Finder first.