3291 Views 7 Replies Latest reply: Jul 5, 2010 4:11 PM by jsd2
You can use your install discs to erase the hard drive, writing 0's to the empty space. This would be enough to delete your data.
If you had any extremely sensitive data on the drive, the best thing to do is remove the hard drive from the machine and install a replacement, or sell the machine without the hard drive.
The proper way to "clean" a computer before selling it is to zero the hard drive. This will make all your data irretrievable.
Steps for zeroing the drive Disk Utility:
1. Insert your Mac OS X CD-ROM disc or Restore DVD disc, then restart the computer while holding the C key until you see the spinning gear.
2. Once started up from CD or DVD, choose Disk Utility from the Installer menu.
Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from disc to access Disk Utility.
3. Choose the entire disk (top icon).
4. Choose erase tab.
5. Click on Options
6. Choose "write zeros".
This will take a bit of time because the computer is physically writing zeros to each block.
You should then re-install the original OS from the system disks and deliver the Mac to the new owner with the system disks that shipped with it.
If you want it to boot as new at startup and create an admin account:
Then, launch Terminal and type:
sudo rm /var/db/.AppleSetupDone
sudo rm -r /Users/yourname
sudo nicl -raw /var/db/netinfo/local.nidb delete /users/yourname/
Then, shut down the machine immediately.
+After installation, when you’re prompted to create a new user, just press Command-Q.+
Excellent! That makes it easy enough
but in case anyone wants to do it the hard way
there's all that cool code you can use
Re-installing the OS as per that article will also re-install the basic apps such as TextEdit or Mail, but it might not automatically re-install the iLife suite that came with the computer - check your original documentation. If not, the "bundled software" on the original discs could subsequently be installed by the buyer, after a user account has been established.