Completely Clearing Your HD (Everything Deleted) -- 35 Pass Secure Erase or Partition

Discussion in 'MacBook Pro' started by Amnesiac1, Feb 17, 2011.

  1. Amnesiac1, Feb 17, 2011
    Last edited: Feb 17, 2011

    Amnesiac1 macrumors 6502

    Oct 11, 2010
    Which is the better method?

    I partitioned my HD first via the install disc but then I thought I'd better erase it as well so there is no residual data. However, when I attempt the 35 Pass Secure Erase, it tells me: "Secure Disk Erase failed with the error: Could not open disk"..

    Is all my data really and completely gone? Or did I just deprive myself (by creating a new partition first) of what could have been a much more thorough erase? I don't want leftover data!

    Thanks for any insight/help that you guys can provide.
  2. Amnesiac1 thread starter macrumors 6502

    Oct 11, 2010
    I'm trying a 7 Pass Secure Erase now... I'm not sure if it's going to work... whenever I click one of these erase options, it tells me that the disk is not formatted.

    I'm worried that... because I partitioned before erasing, the data on my old partition is still taking up space somewhere and, if this old laptop gets sold someday, is still accessible. I hope it's totally gone but how can I be sure? Like I said, I partitioned first and now I'm trying to erase...
  3. Amnesiac1 thread starter macrumors 6502

    Oct 11, 2010
    Okay, I managed to get a "Zero Out Data" operation going...

    Hopefully this will suffice... Will this still be effective even though I'm doing this after[/i] I partitioned my old HD? Will this "Zero Out" process still affect and erase the data that was partitioned over and may still be around (i.e., residual data)?

    EDIT: Nevermind, that just failed, as well. Something about something not being implemented...

    I'm going to go ahead and install Snow Leopard and then return to that screen and hopefully it will let me erase it! Maybe it won't let me erase it b/c the disk is technically empty so there's nothing to erase (technically, that is)?
  4. Erasmus macrumors 68030


    Jun 22, 2006
    Hiding from Omnius in Australia
    Partitioning does not delete data, it simply re-maps the file allocation table things to say it's all empty. All your data is still there, it's just that you don't know where the bits are, or what you're getting until you've looked.

    If you really want your HDD erased, you need to find a way of secure erasing.

    Although, if it's really sensitive data, or you're just ultra paranoid, it would be best to just buy another HD, swap it with your used one, and then just destroy the original. A screwdriver and a hammer and chisel would do it.
  5. Amnesiac1 thread starter macrumors 6502

    Oct 11, 2010
    Apple is replacing my HD and they don't give you back your old HD... If I could manually remove it, though, I would do that before bringing it into them. Can I do that easily?
  6. axu539 macrumors 6502a

    Dec 31, 2010
    Honestly, unless you have some seriously valuable data on there, a single pass zero out should do it. Recovering data from a single zero out is expensive enough, so unless you have something on there that could make someone rich, no one is going to bother.
  7. Amnesiac1 thread starter macrumors 6502

    Oct 11, 2010
    Or should I just install Leopard and then try and do the full 35 Pass Secure Erase? If I do that, will it simply destroy all the fresh Snow Leopard data (i.e., next to nothing besides the OS) or will it dig deeper into the leftover data of my original partition?
  8. Amnesiac1 thread starter macrumors 6502

    Oct 11, 2010
    Yeah, it won't even let me do that, though...

    I wonder why? I suppose b/c the disk is technically 'empty'.

    I wish Apple would just let me keep my damaged HD!
  9. axu539 macrumors 6502a

    Dec 31, 2010
    Oh I see what you're having trouble doing. In disk utility, you have to click on the actual partition (usually named Macintosh HD). Then, hit "Erase Free Space..." under "Erase," which should then give you options. Does that help? I couldn't find it a while back either, and realized you can't zero out the actual disk, only the mounted drive with the data on it (if that makes sense..). If that's not the issue, sorry I couldn't be of more help.
  10. 0007776 Suspended


    Jul 11, 2006
    If you have such valuable information on there that you actually need to do that thorough of an erase the better way to do it is to take the disk out and physically destroy it. But I'm guessing you're just being a little paranoid about your data, so if your computer thinks the HD is empty that is good enough, it's not likely that someone will try to recover your data.
  11. Amnesiac1, Feb 17, 2011
    Last edited: Feb 18, 2011

    Amnesiac1 thread starter macrumors 6502

    Oct 11, 2010
    I can't do that. I have to take this into Apple to be repaired and they would probably have a problem with me doing that. I think, anyways.

    I wonder if I can insist on having my damaged HD returned to me... I wonder if they are at all flexible about that... probably not, as Apple probably wants to make money off the hardware in some way.
  12. Amnesiac1, Feb 18, 2011
    Last edited: Feb 18, 2011

    Amnesiac1 thread starter macrumors 6502

    Oct 11, 2010
    Okay, I'm trying this and it seems to be working!! I am currently erasing the free space. Will this take care of all my worries, though?

    I mean, I am deleting "Macintosh HD" but it is the new partition, right. So, will this erase of free space only pertain to that new partition or should it be so thorough as to erase the first (older, original) partition's data too (that is, the partition I overwrote but whose data is still around apparently)...

    In other words: by adding a new partition first rather than erasing my original HD data, did I deprive myself of the chance to FULLY delete that original HD data or will a thorough (i.e., 7 step delete) of the new partition also delete the older files? Will deleting free space on a new partition get rid of the old left over files from the previous partition?
  13. Miss Terri macrumors 6502

    Nov 11, 2010
    US East Coast
    Just out of curiosity, since you are going to be giving up this hard drive, why did you create a new partition?

    Having said that, I may be asking a stupid question, since I'm not an expert (atlhough I have erased a few hard drives before giving them up to Apple and/or selling computers).
  14. skidmarc macrumors member

    Feb 10, 2011
    FIrst off, if your harddrive is damaged, which you have stated a few times, how does it still work?

    Nonetheless, delete all your partitions, create one partition, call it whatever, once the partition is created, then perform a 7-pass wipe. Do this through the OS disc as if you were installing OS X, as I doubt OS X is stupid enough to allow you to format the partition the OS is on while the OS is running. I could be wrong.

    A 7-pass wipe will get rid of everything on your HDD and make it nearly impossible to recover any data off of.

    Writing 0's to the HDD will also work as stated before and takes less time than a 7-pass.

    If this doesn't work for you then I suggest you take the drive out and destroy the platters, or if you can find magnets of sufficient strength (stronger than the ones on your fridge) to damage portions of the data.
  15. snaky69 macrumors 603

    Mar 14, 2008
    Out of curiosity, what data is so crucial that you are afraid an apple store employee(which will most likely stick your old HD in the trash before putting in a new one and installing OS X) that you need to do a 35pass erase before sending it out? You work for the CIA or something?

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