Password Protect an External Drive in Mac OS X with Encrypted Partitions

We recently showed you how to password protect files and folders using encrypted Disk Images in Mac OS X, but if you have an external drive you can go a step further. By using encrypted disk partitions, any drive, be it a USB key, flash drive, hard disk, or whatever else, can be set to require a password before the drive can be mounted and the files accessed.

Require a Password to Access External Drives with an Encrypted Partition

Doing this will format the external drive and erase all of it’s contents. Back up your data and all contents before proceeding, and do not lose the set password.

1. Launch “Disk Utility” from /Applications/Utilities/
2. Connect the drive you want password protected
3. Select the drive in Disk Utility, and click on the “Erase” tab
4. Pull down the “Format” menu and choose “Mac OS Extended (Journaled, Encrypted)”



5. Click on “Erase”
6. At the next screen, set a password – do not lose this password or you will lose access to the drives data
7. Set a hint that isn’t obvious and then click on “Erase”



8. Let Disk Utility run, when finished the drives partition will show up on the desktop, the drive will be accessible for now without a password allowing files to be transferred over. Eject the disk when finished to require a password upon further mounting and usage.

Once the drive has been ejected, connecting it again will require a password before it is even mounted. That screen will look like this:

Clicking on “Remember password in keychain” will allow the drive to be mounted on the Mac without entering the password on that Mac, but it will still require a password to be used on another Mac. For maximum security, it’s best to leave that option unchecked.

For system-wide security measures, don’t forget to password protect a Mac with both login and screen saver passwords, and if you don’t mind the trade offs, to use FileVault to encrypt the entire hard drive and its contents.