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Are there any free tools to wipe the user contents of a Macintosh running OS X v10.5.8 to keep the operating system and software products installed but remove any user data for selling the computer to another party?

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This won't help you solve this issue right now, but I usually take a time machine backup of any new Mac I buy, before I've done ANYTHING to it, so I can restore it back to "factory" before selling it or giving it to someone. Easier than reinstalling from scratch in most cases. Just for future reference. –  Paperlantern Mar 13 '12 at 20:55
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+1, agree - I'd wipe it and reinstall OS X from scratch, which is probably the safest route. Takes a while though. –  JW8 Mar 13 '12 at 21:00
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up vote 4 down vote accepted

If you want to be completely sure that all traces of your data is removed, both of the "prep for sale" guides (here and here) that I came across recommended wiping your machine's drive and reinstalling OS X. The good news is that you can accomplish this without purchasing or installing any additional software - just back up your data and use Disk Utility to wipe the drive.

Apple Toolbox's guide recommmends:

  • Back up your data. Using Time Machine, or another backup option, make sure your backup is current. Once you complete these steps, there will be no way of retrieving anything.
  • Boot off of your OS X disk. To do this, insert the OS X disk that came with your machine, reboot your computer, and hold down the C key while the machine is booting up. Open Disk Utility. Once your machine has booted off of the disk, and you have selected your preferred language, go to the Utilities menu and select Disk Utility. Once Disk Utility is open, proceed to the Erase tab.
  • Enter a name for the formatted drive. On the Erase tab, enter a name that will be used once the drive is erased. By default, a Macʼs hard drive is named “Macintosh HD.” Since you are preparing to sell the machine, this is a good choice.
  • Select the security level. Below the name field, you will see a button that says: “Security Options.” Once selected, you will be presented with a number of different options. These include: “Do Not Erase Data,” “Zero Out Data,” “7-Pass Erase,” and “35-Pass Erase.” The first option is essentially the same as dragging a file to (and then emptying) the Trash…except that it does it for every single file on the hard drive. Ultimately, however, the data still remains. The other three options erase the data and write zeros over the entire hard drive once, 7 times, or 35 times depending on the option you choose. For most people, the single “Zero Out Data” will be more than sufficient. If your machine has particularly sensitive information on it, such as company financials, trade secrets, or the next great novel, you may want to go with the “7-Pass Erase.” This option is considered secure enough to be the standard procedure for erasing US Department of Defense computers. You can rest easy using this option, while the “35-Pass Erase” is essentially overkill for all but the most extreme cases. Once you have selected the appropriate option, click the Erase button.
  • Install OS X and reboot.

However, the steps here will not leave your existing software in place.

If you're interested in leaving the software and OS X in place, deleting all of your data files, and use Disk Utility to wipe the free disk space. Steps from Apple Support:

Erasing free disk space does not erase the other files on your disk.

  • In Disk Utility, select the disk or volume in the list with the free space you want to erase.
  • Click Erase, then click the Erase Free Space button.
  • Select an option, then click Erase.

You may also want to create a new admin user, delete your old account(s), and run the Disk Utility routine to erase free space used by your account(s).

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You can go a really long way by creating a new admin user account and then using it to delete all the existing user accounts, including deleting their home directories. Then I might delete any existing network "locations" in System Preferences -> Network. And use Keychain Access to clear out most of the System keychain.

I guess there could still be some traces left in /Library, especially /Library/Preferences and /Library/Logs. And maybe /var, especially /var/log.

...Hmm. The more I think about how complicated this problem is, the less I would trust any tool to do a good job of it. I think you really need to just "nuke and repave".

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Not to mention all the non-standard installers that probably leave traces all over the file system, as well as user profile data. –  slhck Mar 13 '12 at 22:01
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