Disk utility - erase hard drive 7 times

Discussion in 'OS X El Capitan (10.11)' started by Vertigoo, Sep 21, 2015.

  1. Vertigoo macrumors newbie

    May 2, 2015
    I don't know if my question has been asked before, but can' t you choose anymore to securely erase the hard drive using the seven times overwrite method?? If not, I think I will stick with OS X Yosemite. Can anyone answer this question please?
  2. MacRobert10 macrumors 6502

    Nov 24, 2012
  3. MistrSynistr macrumors 65816

    May 15, 2014
    CCleaner for MAC will come out and allow you to do this soon for El Capitan I'm sure. I think it offers up to 25 pass overwrite.
  4. beebarb macrumors 6502


    Sep 10, 2015
    So let me get this straight, just because supposedly SSDs don't need secure erase (claim not yet verified), they are going to screw over everyone with traditional and hybrid disks that're uncomfortable performing such tasks in the terminal?

    gg Apple, you managed to really irritate me.
    I don't want to have to use a magnet and sledgehammer to render data on failing traditional disks unrecoverable.
  5. asaggynoodle macrumors member


    Sep 22, 2015

    You're correct. SSD's use an Encryption Key (Can't remember the name), that is randomly generated for the time that the data exists on the SSD. If you delete the Key, even with the data inside still being there it makes no logical sense as it has no method to encrypt the data to even make sense of how the data is stored.

    Basically, it's like having a Foreign traveler and a translator. If you kill the translator and kidnap the hostage to steal the information, it won't matter because you don't know what the foreigner is saying anyways. (Imagine that every person and translator has their own unique language).

    You should just download something like Boot and Nuke and just Option-Run it during boot up off of a bootable USB stick with the ISO burned onto it. You can perform beyond DOD grade formatting there.
  6. flowrider macrumors 603


    Nov 23, 2012
    As I reported in other threads, I downloaded the TechTool Pro Beta 8.03 this morning. I seems to be working fine on El Cap 10.11.1. It includes a setting for erasing a disk called "Wipe Data" that has options for the level of erasure you desire, sort of like the old Disk Utility.

  7. beebarb macrumors 6502


    Sep 10, 2015
    @asaggynoodle While I know I can download Boot and Nuke, I'd rather not have to do so, especially for an external disk, as one wrong move with a bootable utility like that, and I could erase my main disk in error.

    There needs to be a way to do a secure erase within the booted OS X system.
  8. asaggynoodle macrumors member


    Sep 22, 2015
    Oh, I was under the impression for some reason you only wanted to wipe your main disk.
    At any rate, it's pretty well documented which drives are which.
  9. KALLT macrumors 601

    Sep 23, 2008
    No, secure erase is still available for unencrypted HDDs. It has been relocated to the erase panel and will only appear when it can be used (it will not appear with SSDs and encrypted HDDs, both for reasons asaggynoodle stated. SSDs work differently and don’t need to be overwritten like regular HDDs):

    Screen Shot 2015-09-25 at 03.19.24.png Screen Shot 2015-09-25 at 03.19.34.png
  10. Lourdes macrumors newbie

    Aug 24, 2010
    Why would you want to a 7*overwrite? Data overwritten *once* is gone and not coming back, the myth that you have to make multiple passes has been utterly debunked.

    It was a speculative theory that when physically disassembling a drive and using a magnetic force microscopy you might be able to see what had been written in some locations since writes were not always in precisely the same location. Note that seeing a couple of 1's and 0's != recovering any data.

    It's nonsense and nobody has ever managed to do it, least of all on the drives of today which are thousands of times denser.


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