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Hard Drive Erasing for MACs

To erase a Macintosh hard drive you can boot with a MacOS X install CD and use the Disk Utility on the drive.

Apple Tech Note 107437 gives this procedure for MacOS X Systems:

Note: This refers to a full Mac OS X 10.2.3 or later CD included with a computer, not to the update-only 10.2.3 CD.

Steps for zeroing data

These steps assume you have a Mac OS X 10.2.3 or later CD:

  1. Insert the Mac OS X CD.
  2. Restart the computer.
  3. Immediately after the startup sound, press and hold the "C" key to start up from CD.
  4. When the Installer screen appears, do not click Continue. Instead, choose Installer > Open Disk Utilities.
  5. Select the hard drive to erase.
  6. Click the Erase tab.
  7. Select the volume format from the Volume Format pop-up menu.
  8. Click Options.
  9. Select the checkbox for "Zero all data".
  10. Click OK.
  11. Click Erase.

For a more secure method of erasing of data, you can select the checkbox "8 Way Random Write Format" instead of or in addition to selecting "Zero all data." This process could take several hours.

Also for those wanting to "Clean" individual files, note this section from the technote:

Mac OS X 10.3 feature - Secure Empty Trash

You can securely empty the Trash in Mac OS X Panther. While in the Finder, from the File menu choose Secure Empty Trash.

Note: When you securely empty the Trash, the deleted data cannot be recovered by disk utilities. You should only do this if you have a backup or you are sure you will never need the data again.

For machines which boot only MacOS 9 or less use either Drive Setup, Apple HD SC Setup, or Internal HD Format and select the option to zero out and/or low level format the disk. These programs are usually in the Utilties Folder on the install CDs for the various versions of the MacOS. Apple Tech Note 21103 has more information.