Help with secure erase on SSD.

Discussion in 'Mac Basics and Help' started by Caris, Mar 14, 2015.

  1. Caris macrumors 6502a

    Caris

    Joined:
    Sep 25, 2006
    Location:
    Newcastle Upon Tyne, UK
    #1
    Hey everyone, I 'm desperate of advice and need two being things cleared up as I'm confused about something to do with erasing SSD's. Every article on google I search seems to contradict each other and I'm going out my mind.

    Basically it's two questions.

    1) Can I harm the SSD in my Mac by secure erasing it?

    I ask this because I've just got a new 2015 MBP Retina to replace my old one, and for reasons I won't go into I had a little problem with it on the first day and had to restore it. So I done a cmd+r boot and secure erased the SSD with I think it was 3 passes. Then reinstalled Yosemite, could this have harmed anything? Also I'm wiping my old MBP to sell and I done a 7 pass erase on that drive so my data couldn't ever been found with special software, again I want to know if this could have harmed the SSD in any way.

    I have read stuff about these types of erase methods wearing SSD's out, some people say it can make your SSD slower and others have said things like although it "technically" wears it out, other things are more likely to break on your computer before a SSD dies due to age/wear so it's fine to do it every so often.

    See this link for when I asked something similar. Can i harm my SSD secure erasing it?

    2) Why does secure erase in Disk Utility only sometimes show?

    I've noticed in Yosemite and I think Mavericks too, when I have done restores I sometimes have the option to securely my SSD and other times the button is greyed out with "this is not available on your type of drive".

    Is this option only available in certain scenarios or is it a bug?

    If someone could put my mind at rest for all this I would be extremely grateful.
     
  2. Gav2k macrumors G3

    Gav2k

    Joined:
    Jul 24, 2009
    #2
    You shouldn't secure erase an ssd unless you have to and tbh the reason should be a good one.

    The answer to 2? Honestly I don't know never noticed it before.
     
  3. pmau macrumors 65816

    Joined:
    Nov 9, 2010
    #3
    You cannot really secure erase an SSD. The controller will not reveal what chips are erased / written to. In addition you cannot access specific chips to "recover" data.
     
  4. jeremysteele, Mar 14, 2015
    Last edited: Mar 14, 2015

    jeremysteele macrumors 6502

    Joined:
    Jul 13, 2011
    #4
    1) You can "secure" erase an SSD, but it is handled differently than a HDD. If you do a proper SSD erase it'll simply tell the controller (via TRIM) to mark everything as clear. That is good enough (Unless someone took apart the dang drive and checked each individual chip.... Of course modern SSDs are encrypted at the chip level, so even tearing it apart wouldn't work.)

    I don't believe disk utility "knows" how to erase an SSD properly, however. This may have changed in Yosemite, not sure, but I've always used 3rd party tools to do it.

    2) Doing a 7-wipe didn't kill your drive, nor did it harm it that much. You've caused more damage to it by simply using it than doing a wipe. People seem to love reading blogs online an think any writes will kill an SSD. This simply isn't true. Remember, modern SSDs can last tens of thousands of write-cycles per cell. A 7-wipe is nothing in comparison.

    It's completely unneeded to do a 7-wipe though, see #1. Also, even on a magnetic drive it is essentially impossible to recover data from a single wipe. The higher-wipe levels are only there for things like DoD compliance.

    What I would do is create a linux boot USB stick and use something like "ATA Secure Erase" to do the deed. It knows how to handle SSDs.
     
  5. chown33 macrumors 604

    Joined:
    Aug 9, 2009
    #5
  6. BasicGreatGuy Contributor

    BasicGreatGuy

    Joined:
    Sep 21, 2012
    Location:
    In the middle of several books.
    #6
    Turning FileVault (2) on and then booting to Command +R to erase the drive should be sufficient, in my opinion. Then, you can reinstall the OS etc.
     

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