HT201065: What to do before selling or giving away your Mac

Learn about What to do before selling or giving away your Mac
BlueDiamond101

Q: Is it possible to completely remove ALL data when wiping??

Is ALL data completely wiped and irretrievable from my old mac once this process is done? I have heard of others illegally retrieving data from old discarded hard drives previous owners had 'wiped' clear.

Mac mini, OS X Mavericks (10.9.5)

Posted on Dec 28, 2014 8:51 PM

Close

Q: Is it possible to completely remove ALL data when wiping??

  • All replies
  • Helpful answers

  • by dot.com,

    dot.com dot.com Dec 28, 2014 9:06 PM in response to BlueDiamond101
    Level 2 (434 points)
    Dec 28, 2014 9:06 PM in response to BlueDiamond101

    When you erase a drive, you can do it fast/non-secure or slow/secure. Choose the "secure" method and specify 1, 3 or 7-pass option. For large disk drives this can take a VERY VERY LONG TIME. But if you want to be safe, what's a day or two.

     

    The multiple-pass secure options writes different bit-patterns to the drive, before it finally erases it with all zeros, which leaves nothing for anyone to recover later on.

     

    If you choose the unsecure method (the default) it only initializes the information that says how many files are on the drive and where to start writing when new files are created. The actual part of the disk that had your old data is not even touched, so with the right kind of software that information is able to be recovered to varying degrees of success.

     

    The 3-pass secure erase method is what the DOD (Department of Defense) recommends for erasure of drives.

     

    See this for a lot more information about securely erasing disks:

     

    http://www.it.cornell.edu/security/depth/practices/media_destruct.cfm

     

    have fun.....