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How do I set up an offline backup?

Howy the walrus putting a hard drive into a storage box

Keep a copy of your files that your computers can't reach: a drive you unplug after each backup, or a backup service built for the job. Files on your computers go to a drive with File History or Time Machine. Files in Microsoft 365 or Google Workspace need a backup service or a regular export.

An offline backup is a copy of your files that stays disconnected from your computers until you need it. An immutable backup is locked so nobody can change or delete it for a set time.

Check if you already have it

  • Windows: open Control Panel, System and Security, File History. It should show an external drive and a recent backup time.
  • Mac: open System Settings, General, Time Machine. It should show a backup disk and a recent Latest backup.

Then ask three questions about your backup:

  1. Can your computer open the backup files right now, without plugging anything in or signing in somewhere else? If yes, it isn't offline.
  2. If you delete a file on your computer, does it disappear from the backup too? If yes, it's syncing, not a backup.
  3. Does your backup service have a lock or retention setting turned on? Services call it immutability, object lock or retention lock. If it's on, that copy is immutable.

Does your backup count as offline or immutable?

  • External drive that stays plugged in: not offline, not immutable.
  • External drive you unplug after each backup: offline.
  • OneDrive, Google Drive, iCloud Drive or Dropbox: neither, because it syncs.
  • Network drive in the office that's always on: not offline. Immutable only if its lock feature is on.
  • Cloud backup service with its own sign-in: separate, not unplugged. Immutable only if its lock feature is on.

How to set it up

You need an external drive at least as big as the files you're backing up (for a Mac, as big as the Mac's storage) and an admin account.

Files on your computers, on Windows:

Keep a backup on a drive you unplug, using File History

Windows, needs an external USB drive at least as big as your files, and an administrator account

  1. Plug in the external drive.
  2. Open Control Panel, then System and Security, then File History.
  3. Click Select drive, choose your external drive, then click Turn on.
  4. Click Run now and wait for the first backup to finish.
  5. Click Advanced settings and set Save copies of files to Daily if you can leave the drive in for a while each day, or plan a weekly backup.
  6. When the backup finishes, eject the drive and unplug it. A drive that stays plugged in can be scrambled by ransomware along with everything else.
  7. Put a weekly reminder in your calendar: plug in, click Run now, unplug.

How to show it's true: Screenshot the File History page showing the drive name and the latest backup time. Keep the drive somewhere other than next to the computer.

If you get stuck:
  • File History doesn't list your drive: check it shows up in File Explorer first. If it does not, try another USB port.
  • Your client records live only in records software such as Jane: that company keeps its own backups. This backup is for everything else on the computer.

Files on your computers, on a Mac:

Keep a Time Machine backup on a drive you unplug

Mac, needs an external drive at least as big as your Mac's storage

  1. Plug in the external drive.
  2. Open System Settings, then General, then Time Machine.
  3. Click Add Backup Disk, pick your drive, and turn on Encrypt Backup. Set a password and store it somewhere safe.
  4. Click Done, then wait for the first backup to finish.
  5. When it finishes, eject the drive in Finder and unplug it. A drive that stays plugged in can be scrambled by ransomware along with everything else.
  6. Put a weekly reminder in your calendar: plug in, choose Back Up Now from the Time Machine menu, then eject and unplug.

How to show it's true: Screenshot the Time Machine settings showing the drive and Latest backup time. Keep the drive somewhere other than next to the Mac.

If you get stuck:
  • The Time Machine menu isn't in the menu bar: in System Settings, open Control Center and set Time Machine to Show in Menu Bar.

The steps set up a weekly routine. If your form asks for daily backups, plug in, back up and unplug every working day instead.

Files in Microsoft 365 or Google Workspace: follow how to add a real backup to OneDrive or Google Drive. If you need immutable, ask a tech to turn on the backup service's lock or retention feature. Either way, use two-step sign-in on the backup's own login.

How to show it's done

Screenshot File History, Time Machine or your backup service showing the latest backup date, and the lock or retention setting if you have one. Note where the drive is kept. Then test a restore and save a dated note of it. File both in your proof folder.

Common questions

How many copies should I keep?

Two drives you swap each week, with one always away from the office, is a simple setup for a small business.

Can I leave the drive plugged in if it backs up every night?

Not if you want to call it offline. It only counts once it's unplugged.

Does a cloud backup count as offline?

It's separate, not unplugged. Some forms accept a backup service built for the job. If yours only says "offline", ask your broker.

Is iCloud a backup?

iCloud Drive syncs, so on its own it isn't a separate copy of your work files.

Does the backup need a password?

Turn on Encrypt Backup in Time Machine, and use two-step sign-in on any backup service. Store the password away from the drive.

Sources

  1. Canadian Centre for Cyber Security: Tips for backing up your information (ITSAP.40.002)cyber.gc.ca
  2. Microsoft Support: Backup and restore with File Historysupport.microsoft.com
  3. Apple Support: Back up your Mac with Time Machinesupport.apple.com
  4. Microsoft Learn: Store business-critical blob data with immutable storagelearn.microsoft.com

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