Why are all my deleted files recovered even after a Secure Erase?

Discussion in 'macOS Sierra (10.12)' started by macpokerstars, May 23, 2017.

  1. macpokerstars macrumors member

    Joined:
    Sep 29, 2010
    #1
    I did a seven pass secure erase on my free space on my hard drive (conventional HD, not SSD). using this command:

    diskutil secureErase freespace 2 "/Volumes/Macintosh HD"

    After it was completed, I used Disk Drill to check whether it could recover deleted files and it did.
    It looks like secure erase is not working.

    How can I securely erase free space on my hard drive?
     
  2. treekram macrumors 6502a

    Joined:
    Nov 9, 2015
    Location:
    Honolulu HI
    #2
    Did you empty the trash before doing the secureErase? The other possibility is if you have a laptop with Time Machine as I believe there is a file that can get created with a backup of some of your files (I can't remember the exact details). Also, some programs will make copies of files. For example, by experience I know that TextEdit makes a copy of the file you're editing but haven't saved every so often in case of an unexpected shutdown (in my case, there was a power outage and when I turned the machine back on, TextEdit re-opened the file which I did not save).
     
  3. Weaselboy Moderator

    Weaselboy

    Staff Member

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    Jan 23, 2005
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    California
    #3
    Yeah... that might be it too. It is called local snapshots and is stored in the hidden folder at /.MobileBackups .
     
  4. macpokerstars thread starter macrumors member

    Joined:
    Sep 29, 2010
    #4
    Hi there,
    Thanks for your response. I have never used Time Machine.
    My computer spent 5-6 hours secure erasing free space on my 1TB hard drive, but Disk Drill finds all deleted files effortlessly and they are intact.
    Please let me know if you have any suggestion.
    Thanks
     
  5. BeefCake 15 macrumors 65816

    BeefCake 15

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    May 15, 2015
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    near Boston, MA
    #5
    Have you tried it through a third party software? CCleaner or others?
     
  6. macpokerstars thread starter macrumors member

    Joined:
    Sep 29, 2010
    #6
    No I haven't. I just downloaded it and will post the results.Thanks for the suggestion
     
  7. Yahooligan macrumors 6502a

    Yahooligan

    Joined:
    Aug 7, 2011
    Location:
    Illinois
    #7
    Looks like you skipped over the other question that was asked; Did you empty the Trash before running the secure erase?
     
  8. KALLT macrumors 601

    Joined:
    Sep 23, 2008
    #8
    Apple discourages the use of this command due to its limitations. You should not use it. Either you encrypt the disk or erase it completely.

    Moreover, a 7-pass overwrite is considered unnecessary, a single-pass, zero-fill erase is generally sufficient.
     
  9. macpokerstars thread starter macrumors member

    Joined:
    Sep 29, 2010
    #9
    I tried CCleaner and unfortunately, it changed nothing. Even after I did a 7-pass THEN a zero-out of the free space, Disk Drill still found every single file that was there before. I erased previous Disk Drill sessions, but it still found all files again.

    Yes I did but it didn't help, unfortunately.
     
  10. BeefCake 15 macrumors 65816

    BeefCake 15

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    May 15, 2015
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    near Boston, MA
    #10
    Did it find the file still functional or just metadata?
     
  11. BLUEDOG314 macrumors regular

    BLUEDOG314

    Joined:
    Dec 12, 2015
    #11
    I was thinking this too. It's possible its just seeing like the directory entry for the stuff?
     
  12. treekram macrumors 6502a

    Joined:
    Nov 9, 2015
    Location:
    Honolulu HI
    #12
    I would suggest the following: Buy an external 1TB HDD. Clone your internal HDD to the external. If you don't already have cloning software, you can get CCC free on a trial basis. (CCC is good for this purpose because the current version will copy files, not sectors - for what you want to do, you don't want software that will copy sectors). Format and erase the internal HDD using a 2-pass or whatever. See if Disk Drill can find the files. It should not be able to find the files on the internal HDD. Then see if it can find the files on the clone. If it can find the file on the clones, then you didn't delete some file that contains your data. If it can't find the files, then you have a method that will work for secure erasing.

    Let us know how it turns out.
     

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