Securely Wipe an iMac or Mac OS X Based System Hard Drive
Read this if you would like to learn how to securely wipe an iMac or later Apple-based hard drives/partitions. This information is useful for clearing out any private data that you may have on your system prior to giving your system to a friend or selling it to someone else...
Note that this process is irreversible, so be absolutely sure that you would like to erase your data.
Contents
Steps
- Boot an iMac or Apple-based higher system.
- Make sure you've backed up all your necessary data to a thumb or external hard drive. This data includes important documents, media, Itunes files, and bookmarks.
- Safely remove this thumb or external hard drive so that it is no longer connected to your system.
- As a precaution, physically detach all connected disks that you do not wish to wipe. If you leave them attached, they may get accidentally overwritten and you will not be a happy camper.
- Insert an OS 10.4 System disk. Use a CD if you have a CD drive or a DVD/CD if you have a DVD drive.
- Restart your system. Go to Apple Menu - Restart. Click Restart when prompted.
- Your system should boot the CD. If it doesn't, you may need to restart again and hit the C key to boot the disk.
- In the localization (languages) dialog, choose an appropriate language for your needs, or choose Use English as the main language.
- Wait a few seconds while a Preparing Installation screen displays.
- If you have an early-style iMac system, you will get an Alert message that says: Alert - Your computer is not compatible with Mac OS X 10.4. If so, ignore the message for now. Although you can't install 10.4 on this early-style iMac system, you can use the 10.4 System Disk utility to wipe your system clean.
- At the top of your screen, click Utilities Menu - Disk Utility.
- Wait for the Disk Utility program to start up.
- On the left hand pane, highlight the drive and/or partition you'd like to securely erase.
- On the right hand pane, click the Erase tab.
- On the right hand pane, choose Security Options...
- Choose 7-Pass Erase. Choose 35 if you really want to be sure, but that takes much more time and may be overkill.
- Click OK.
- On the Right Hand Pane, click Erase.
- Read the confirmation message and think about it.
- If you're sure, go ahead and click Erase.
- Wait many hours for the Erase procedure to take place. When it is completed, there are no helpful messages indicating that it's completed successfully.
- At the top of the screen, go to the Disk Utility Menu - Quit Disk Utility.
- At the top of the screen, go to the Installer Menu - Quit Installer.
- Press and hold the power button for a few seconds to restart your system.
- As soon as you hear the restart "boing," eject the 10.4 CD/DVD.
- Remove the disc and stow it away.
- You now have cleared the entire partition(s) and/or drives. Note that if you have cleared the system drive, the system will not boot. This will be your opportunity to install a fresh operating system, if you wish.
Tips
- The system disk you use must be 10.4 or later. 10.4 or later contains a special version of Disk Utility that securely wipes drives.
Warnings
- Back up all your important data. Neither I nor this website accept any responsibility for any accidental data loss that you may encounter. Follow these instructions at your own risk.
- Note that this process is irreversible, so be absolutely sure that you would like to erase your data.
