Will A Format Erase EVERYTHING?

Discussion in 'MacBook Pro' started by mikeyPotg, Oct 9, 2007.

  1. mikeyPotg macrumors 6502

    Mar 20, 2006
    Hey guys,

    I'm a teacher and one of my students is interested in buying my MBP. I'm just wondering though, since my student is incredibly computer/hacking savvy, if I do a fresh install of the OS on my MBP, would there still be any chance of him finding any old files and/or data?

    Or is it good to go?

    Thanks all,
  2. killmoms macrumors 68040


    Jun 23, 2003
    Washington, DC
    Technically, if he had access to low-level data recovery tools, he could... but it's not really that big a concern. Certainly there are probably only a few critical files you wouldn't want recovered (passwords, financial information, that sort of thing). Once you've backed up your stuff, you could secure delete JUST those things (since a secure format of an entire hard drive takes a really long time). Then do a regular format and reinstall the OS and you'll be golden.
  3. hamholio macrumors member

    Jun 22, 2006
    Whenever I sell one of my Macs, I put the install disc in, reboot from the disc and then, under Disk Utility, I believe, use one of the safe Hard Drive Delete set ups. Usually the one that overwrites the entire hard drive 7x with 1s and 0s.
  4. skunk macrumors G4


    Jun 29, 2002
    Republic of Ukistan
    I usually just take out the disk and wash it in hot, soapy water.
  5. Freyqq macrumors 601

    Dec 13, 2004
    i think there's an option when you install the OS to do a low-level format (they might call it something else). This scrambles the code on the hd before it installs the OS..making it much much much more difficult to find stray files.
  6. Sun Baked macrumors G5

    Sun Baked

    May 19, 2002
    Format just erases the links to the file catalog.

    Personally I'd just copy a short Barney sings something very annoying clip over and over onto the blank drive.

    Doesn't really take that long completely fill the drive, and leaves something worthwhile on the drive to find when you reformat it again. :p
  7. Merlinus macrumors newbie

    Jun 22, 2007
    There are a number of options you can use to clear your disk, with varying degrees of success.

    The method mentioned above is one that's pretty common - zero fill or overwrite your entire harddrive with either 0s and 1s using 1, 2, 7, or 35 passes. However, there are a number of articles out that claim even 35 passes won't ensure that your data is fully secure (especially in bad sectors of the hdd which would've been sectioned off and where the formating couldn't easily access).

    The recommended method is to physically shred the HDD. There are some industrial tools for doing this, with a combination of strong magnets and metal shredders. Alternatively you could simply destroy the HDD using a hammer and nails. Be sure you destroy the actual disks inside the casing and not just the head and outer enclosure (i.e. drive many many nails through the thing). Soaking it in water and other chemicals helps, but physical damage is the best bet.

    This all depends on just how far your student would go to access your old data of course. If you use the 7 or 35 pass method above, it's doubtful he could recover all your files in their entirety, but maybe just fragments. Of course, if he hires a professional data recovery company or gets the government involved, the chances of recovering your data can be substantially increased - this applies to everything short of fulling shredding the disk. Good data recovery companies can recover even waterlogged HDDs.

    Obviously, physically shredding the HDD and replacing it with a new one would be the safest method.
  8. sndcj1 macrumors member

    May 22, 2007
    unless your student works for the FBI...

    a zero out data, or 7 times overwrite will suffice. The theoretical ability for someone to get data off a drive that has been overwritten like this requires the person to remove the platter from the drive, and "manually" scan it with VERY expensive equipment to find echo's of files, then try to recreate the real files from that. The standard "Undelete" applications you can buy anywhere will find files that have not been overwritten, and can sometimes get file fragments and give you recreated partial files, none of which would exist on a wiped drive. As others have said, do this from the install disk, as file fragments can be left with standard data overwrites. The sensors used by the hard drive will not be able to read overwritten data. I would suggest doing a full wipe (not just reformat) and re-install.
  9. tradosaurus macrumors newbie

    Oct 3, 2007
    Sounds to me like you shouldn't sell your laptop to this student. :rolleyes:
  10. Transeau macrumors 6502a


    Jan 18, 2005
    Alta Loma, CA
    Just move your private stuff to the trash can, the "Securely Empty Trash". Format and Reinstall, install updates...

    If the kid has access to the tools needed to recover any of your private information, then it's the least of your worries as he's already stolen your identity. :)

    In my daily work, I use the tools and it's still hard to recover anything of value after those steps.
  11. cecemf macrumors regular


    Sep 24, 2007
    London, UK
    Hi i'm actually saling my Macbook Core duo and will buy on the 15th Only (Leopard in iMac date) and i would like to format it and reinstall MacOSX from scrash like he just bourght it !

    But i am a ex windows user and has i never had to format my Mac i don't know how to do it !!! how to i do for my Start up CD to boot on starter ? and what do you recommend guy's ?
  12. Transeau macrumors 6502a


    Jan 18, 2005
    Alta Loma, CA
    Put in the DVD, and double click the Install icon.. it's very simple.
  13. deadpixels macrumors 6502a

    Oct 30, 2006
    hold Command-C to start up from your install DVD. you can then use the disk utility (in the apple menu) to format the way you want. it'll be faster if you do the formating when booted from a firewire ext. hard drive for example.

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