Mac OSX El Capitan Secure Erase

So, it’s time to give my old corporate Macbook Pro 15″ back to who knows where.

Time to move my data to my new (much the same) Macbook Pro 15″ and secure erase my old SSD.. Right?

Wrong! Seems the recovery partition on El Capitan (Hold down CMD + R on boot) completley prevents any of the ‘secure erase’ options; the button for security options just isn’t there!

Anyway, the disk utility is just a pretty GUI on the ‘diskutil’ command line.

So, to run a very secure (and lengthy) 35-pass wipe on your main disk…

once you have the “OSX Utilities” window showing, goto Utilities > Terminal from the menu bar, then on the terminal type the following command:

 diskutil secureErase 3 disk0 

For a quicker, US DoD 7-pass secure erase, run:

 diskutil secureErase 2 disk0 

Or an even quicker, US DoE 3-pass secure erase, run:

 diskutil secureErase 4 disk0

If the command errors with “device in use” you’ll need to unmount your MacOSX partition first with the following command:

 diskutil unmountDisk disk0 

WARNING: Any of these options will permanently, irreversibly destroy ALL data on your disk. Please make sure you have no external storage directly attached, or you may just wipe that instead.

The secureErase commands will then show a progress bar and estimated time to completion. The 34 Pass wipe on a mid-2012 256GB SSD estimates 8 hours.

Yes, you’re going to need a charger 😉


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