What to do before you give away a Mac: 3 things you should do to protect your data
When you buy a new Mac, you may choose to sell your old one or give it to a family member, friend, school or charity. If so, there are a few things you need to do to clean house and remove all traces of your personal information.
1. Deauthorize It: If you use the iTunes Music Store or Audible.com, you’re limited in the number of computers that can be authorized to play back music or audiobooks. You therefore need to deauthorize your Mac. In iTunes, select Advanced: Deauthorize Computer, select which account to deauthorize, and follow the instructions.
2. Erase Everything Securely : delete all the files on your hard disk. Don’t just delete them, but zero the disk completely. Using Disk Utility, you can write zeroes to the entire disk making it impossible for all but the NSA to find remnants of your files. Boot from an installation CD or DVD, then select Tools: Disk Utility after the installer launches. Select your Mac’s hard disk, then click the Erase tab. Select Security Options, and choose the Zero Out Data option (or 7-Pass or 35-Pass erase if you’re really paranoid). Click Erase. (The multiple-pass erases will take a while, so make sure you’re not in a hurry.) If the disk was partitioned, you should select the disk first, click the Partition tab, then re-partition it to a single volume, unless you’re sure the new user wants to keep it as is.
3. Make It Factory Fresh: Reinstall the original system that came with the Mac. Use the original system disc(s) (CD or DVD), and note the user name and password for the first user account you create after installation. If you want, after you’ve deleted everything on the hard disk, as explained above, quit the installer. Then find all the discs (CDs or DVDs) that came with the Mac to give to the new owner. —Kirk McElhearn