Mac cannot read MS DOS external hard drive

Discussion in 'Mac Basics and Help' started by dorothigna, Nov 16, 2015.

  1. dorothigna macrumors newbie

    Joined:
    Nov 16, 2015
    #1
    Hi everyone,

    I'm a very newbie here and in the Mac world,
    so please tell me if this is not the right forum to post about it.

    I haven't found any other thread about my issue but please also tell me if I just missed it.

    I have a MacBook Pro Retina 13", and I updated to El Capitan this morning.
    I also have a 4TB ISY external drive which has been formatted and partitioned as MS-DOS.
    It already contains files.

    When I switch on the hd I get the error message (see attachment 1, in Italian, but should be understandable):

    "The connected disk is not readable by this computer"

    Then I ignore the message and open Disk Utility, you see what I get in attachment 2.
    As you can see it is not possible to activate the disk.
    So I tried with the SOS option and this is what the final log says (attachment 3, lines 5-6):

    "Some issues with the map of partitions have been identified, which might prevent the (disk) launch"

    I really have no idea of how to proceed in order to be able to read and write the disk from my new Mac,
    and I thank you in advance for any help :)

    Dorothea
     

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  2. chscag macrumors 68000

    Joined:
    Feb 17, 2008
    Location:
    Fort Worth, Texas
    #2
    This WD disk must have originally been formatted to NTFS and not MS DOS (FAT or exFAT). Did you change the format and what did you use to partition the drive? Answer that for us. The message you're getting sounds like the drive is still formatted to NTFS but now in 3 partitions. If that drive is still formatted to NTFS you won't be able to write to it without special software.
     
  3. dorothigna thread starter macrumors newbie

    Joined:
    Nov 16, 2015
    #3
    Hi chscag,
    thanks for your reply!

    Although the hd it pretty new (bought about 1y ago and barely used since then),
    it wasn't mine in the beginning so I don't know much about it.
    I haven't even formatted it, but if there is any way I can get all these infos just tell me what to do.

    What I know is that, when I tried to mount the hard disk from Yosemite,
    right bedore updating to El Capitan, Disk Utility told me the format of all the three paritions was MS-DOS (FAT),
    as you can see in the attachments.
     

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  4. BrianBaughn macrumors 601

    BrianBaughn

    Joined:
    Feb 13, 2011
    Location:
    Baltimore, Maryland
    #4
    Have you tried a different cable? Have you tried the drive on a different computer?
     
  5. dorothigna thread starter macrumors newbie

    Joined:
    Nov 16, 2015
    #5
    Sorry for my late reply.

    I cannot try with a different cable as all the others I have here have different plugs,
    but I guess the cable shouldn't be a big problem since it's rather new.

    I tried the drive on a Dell Latitude using Fedora and it works perfectly,
    everything is there and I can either read and write the disk.
     
  6. chscag macrumors 68000

    Joined:
    Feb 17, 2008
    Location:
    Fort Worth, Texas
    #6
    I understand that. However, the drive had to be formatted originally as NTFS because the FAT format can not exceed 2 TB. And it appears that it was partitioned and the format changed to MS DOS (FAT) which can create problems. There is something about the structure of the drive that OS X doesn't like.

    Your Dell Latitude is running Fedora Linux and is able to read and write. BTW, Fedora like Ubuntu can read and write to different formats besides FAT.
     
  7. dorothigna thread starter macrumors newbie

    Joined:
    Nov 16, 2015
    #7
    I see, thanks for clarifying!

    The only thing is that, since the main content of the hd is high resolution pictures,
    I would like to be able to access those files from the Mac, which has been actually bought for its awesome Retina screen.

    Is there any app or additional software I can install to use the hd normally?
     
  8. BrianBaughn macrumors 601

    BrianBaughn

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    Feb 13, 2011
    Location:
    Baltimore, Maryland
    #8
    Normally...on just OS X or do you want to be able to access it on other systems?
     
  9. dorothigna thread starter macrumors newbie

    Joined:
    Nov 16, 2015
    #9
    On just OS X would me more than fine at the moment!
     
  10. BrianBaughn macrumors 601

    BrianBaughn

    Joined:
    Feb 13, 2011
    Location:
    Baltimore, Maryland
    #10
    You've got to figure out how to copy the files to something else (computer, drive), format the 4TB drive for Mac, and then get the files back on it. If you don't have a backup of that stuff now is the time to come up with a plan.
     
  11. dorothigna thread starter macrumors newbie

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    Nov 16, 2015
    #11
    Do you mean I have no other option but formatting the hard disk again?
     
  12. BrianBaughn macrumors 601

    BrianBaughn

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    Feb 13, 2011
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    Baltimore, Maryland
    #12
    Yes. That's the software you have to "install to use the hd normally."
     
  13. dorothigna thread starter macrumors newbie

    Joined:
    Nov 16, 2015
    #13
    I thoght I could install some program to access the data as for the NTFS format.
    Ok... If there is no other possibility then I'll move the data and reformat the hd.
    I hope it isn't too difficult though, as I've never done it before...
     
  14. dorothigna thread starter macrumors newbie

    Joined:
    Nov 16, 2015
    #14
    I am checking instructions to format the disk and it seems quite a straightforward procedure though...
     
  15. BrianBaughn macrumors 601

    BrianBaughn

    Joined:
    Feb 13, 2011
    Location:
    Baltimore, Maryland
    #15
    There is third-party software to allow read/write of NTFS disks but you responded "just OS X" so I didn't mention it.

    Either way you still need to reformat that drive.
     

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