Mac OS X Lion: How to Encrypt External Drives

Backing up your data is one of the most important steps in making sure you data is safe. Adding encryption to your backups is even better. Here’s how to encrypt external drives in Mac OS X Lion.

This process lets you encrypt USB External hard drives, flash drives and SD cards. OS X Lion uses Filevault2 with XTS – AES 128 bit encryption to keep your backed up data secure.

Plug the external drive you want to encrypt into your Mac. Then click Go >> Utilities from the toolbar.

Mac Toolbar

Then double click on Disk Utility.


When Disk Utility launches, find the external drive on the left and highlight it. Here I am encrypting a 16 GB flash drive. To add encryption, you’ll need to format the drive. So make sure any data you need on it is backed up first.

Disk Utility

In Disk Utility, click the Erase tab. Then select the encryption format to use. For best results use Mac OS Extended (Journaled, Encrypted).

Disk utility Erase

Type in a memorable name for your drive. Then click the Erase button.

name drive OS X

Then you’re prompted to enter a secure password twice to start the encryption process. Use a strong password with a lot of upper and lowercase letters, numbers and symbols. The stronger the password the better! Disk Utility shows a password strength meter while typing the password in.

If you want, type in a hint for your password – but it’s not required. Click the Erase button.

Enter Password

Disk Utility formats and encrypts the drive. You’ll see a progress bar in the lower right corner of the utility window.

format process

You’re all set. Add your secret files of world domination to the encrypted drive.

add files

Then eject it safely.

Eject drive

The next time you plug your drive into your Mac, you’re prompted for the password you created for the encrypted volume. I don’t advise enabling the option to remember the password in the keychain – especially on a shared computer.

encrypt password

After entering the password, click Unlock. Now you’re able to access the files on the encrypted drive.

Files encrypted drive

Keep in mind that the encryption protocol will only work on a Mac. You can use Disk Utility to format your external drive to (MS-DOS) FAT, but it won’t be encrypted. A great program to encrypt your drive so it works with Windows, Mac and Linux try TruCrypt.

While you’re at it, make sure to encrypt your iPhone, iPad or iPod touch backups too.



  1. Santosh

    February 18, 2012 at 10:38 am

    Is there something similar to this Encryption mechanism available in Windows 7 Ultimate?

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    September 11, 2013 at 12:54 am

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