how do I verify bad blocks?

Discussion in 'Mac Accessories' started by ScottR, May 19, 2018.

  1. ScottR, May 19, 2018
    Last edited: May 19, 2018

    ScottR macrumors member

    Joined:
    May 11, 2007
    #1
    Drive Genius 5 has found significant media problems with a 3 month old 6GB Western Digital USB 3 drive (see screenshot).

    I have the data (mostly) backed up, but I'm rather taken aback at this. What are the odds these are false positives? How can I verify this report? Since DG gives location information for the "damaged physical area" is there any way to verify those particular areas? (i.e., since scanning all of a 6TB drive would take a really long time I'd like to check the specifically reported areas)

    Disk Utility sees no errors, though I presume it's not checking the whole drive. DG5 is running checks in the background.

    wd.jpg
     
  2. keysofanxiety macrumors G3

    keysofanxiety

    Joined:
    Nov 23, 2011
    #2
  3. chabig macrumors 603

    Joined:
    Sep 6, 2002
    #3
    From the user guide:

    6.4.1 Revive damaged areas
    Most modern drives will automatically reallocate any bad data areas they encounter to another area on the drive. Each drive has a reserved amount of space to handle these reallocations.

    If Drive Genius or DrivePulse informs you it has found bad areas, or you suspect there are bad areas on a drive you can enable Revive damaged areas to allow Drive Genius to instruct the hard drive to reallocate any bad data areas that are found.

    When Drive Genius finds a bad area, it will attempt to read the information from the bad area and write it back to the same area. This will kick-in the drive’s reallocation mechanism and move the data area contents to a new area.
     
  4. ScottR thread starter macrumors member

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    May 11, 2007
    #4
    The drive passes the SMART test.
     
  5. chabig macrumors 603

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    Sep 6, 2002
  6. keysofanxiety macrumors G3

    keysofanxiety

    Joined:
    Nov 23, 2011
    #6
    In which case, she's fine.

    (definitely the internal drive you checked? SMART Utility will by default only pick the boot drive, unless the disk in question was the boot drive)
     
  7. ScottR thread starter macrumors member

    Joined:
    May 11, 2007
    #7
    It was a USB drive that’s having the issues, and yes I checked it.
     
  8. BrianBaughn macrumors 603

    BrianBaughn

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    Feb 13, 2011
    Location:
    Baltimore, Maryland
    #8
  9. keysofanxiety macrumors G3

    keysofanxiety

    Joined:
    Nov 23, 2011
    #9
    Oh OK, it's just SMART data doesn't natively work for USB drives in macOS IIRC, not sure if that's changed on newer versions. Best to check without the drive plugged in & then check with plugged in.

    If the drive shows up as an additional one when it is plugged in and it still comes back clean, all good. If not, you'll need to download SATSMART, then restart your machine to enable macOS to be able to read SMART data from external drives & then check again.
     
  10. ScottR thread starter macrumors member

    Joined:
    May 11, 2007
    #10
    It's possible I installed something along those lines once upon a time, because it's definitely testing and passing the drive in question.

    smart.jpg
     
  11. keysofanxiety macrumors G3

    keysofanxiety

    Joined:
    Nov 23, 2011
    #11
    Gotcha buddy, just wanted to be absolutely sure. :)

    Yeah, the drive's fine, no cause for concern.
     
  12. ScottR, May 30, 2018
    Last edited: May 31, 2018

    ScottR thread starter macrumors member

    Joined:
    May 11, 2007
    #12
    Ran Drive Genius last week (the full app, not the background monitor that found the problems) and it returned lots of errors. So I set up a RMA and went to zero the drive before returning. But Disk Utility returned the following: ""Unable to write to the last block of the device."

    I looked up the error and this was one of the results that came back.

    That gave me pause. So I swapped out the USB 3 cable (it came with the drive) with another I had and ran Drive Genius's Physical Check. Twice. Each time it passed successfully!

    I'd been communicating with Prosoft about this, so I sent them the latest. Their reply: "It is possible that if there was a faulty connection causing issues when those particular blocks were checked, it would report them as being unable to be read. If you are no longer receiving errors with the new cable, you should be able to continue using the device however I would recommend making a backup as a precaution if you have not already done so."
     

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