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I have my Time Machine backups on an external disk (WD My Passport with no hardware encryption) and I'm worried if the data stored on the disk is safe in case somebody steals it and connect it to any Mac/PC.

Does any Mac can browse the Time Machine backups? Or are they encrypted in any way?

If no, is there a way to improve security of the backups, should I buy a hardware encryption based HD?


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up vote 12 down vote accepted


There is zero encryption applied by default to a Time Machine backup.

Although you may not be able to just 'load' a Time Machine backup from another computer easily, I would imagine that it would be very trivial for someone to actually view the files as no special effort is made to protect them like this.

Edit: As Arjan said, "Loading it is as easy as holding down Option to change "Enter Time Machine" into "Browse Other Time Machine Disks"."

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Ah I see, but yes, anyway all the files are visible for anyone. I'll consider switching to a hardware encryption based disk, what do you think? – Leandro Ardissone Oct 23 '09 at 15:40
Loading it is as easy as holding down Option to change "Enter Time Machine" into "Browse Other Time Machine Disks". – Arjan Oct 23 '09 at 15:41

This answer is not complete.

For a home directory secured with FileVault 1

Backups of that home, performed by Time Machine, will be as secure as the original.

For a home directory secured in this way:

  • runs of Time Machine whilst the user is logged in will exclude the home
  • a run of Time Machine, for the secure home, will occur whenever the user logs out.
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And that means extra time on shutdown? – Leandro Ardissone Oct 23 '09 at 17:15
It means you cannot shut down until you know the backup is ready. It also means you cannot restore individual files: (I think it actually means you should use some other way to backup things then...) – Arjan Oct 23 '09 at 17:29
You still can do backups, but only when logging out, hence, you probably will do them more like once a day instead of every hour. You backups are only good for full system restores but not for individual files. Personally, I am fine with this and use Dropbox for the missing hourly backup (well, more like secondly backup ;-)) – bastibe Oct 23 '09 at 18:18
A small clarification. Time Machine does not encrypt anything. But if it backups up the FileVault DMG file, that is encrypted (due to File Vault, not Time Machine). Beware! When you start File Vault, it adds the users home directory to the exclusion list of Time Machine. If the user removes that exclusion, his unencrypted home folder will be backed up, defeating File Vault. – Benjamin Schollnick Oct 23 '09 at 18:39
@Arjan for Time Machine backup of a FileVault 1 home directory: it's not necessary to shut down. Log out suffices. – Graham Perrin Jul 24 '12 at 9:08

If you're using OS X 10.7 Lion there's now an option to "Encrypt Backup Disk" from Time Machine. You might want to take a look at this tutorial: How to backup your Mac securely using Time Machine on OS X Lion

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