WD 4TB - Yosemite - Disk Not Readable

Discussion in 'OS X Yosemite (10.10)' started by HelixOmnimedia, Oct 20, 2014.

  1. HelixOmnimedia macrumors 6502a


    Jul 26, 2006
    Traveling The World

    Need any help or advice given. Gave a friend my external My Book 4TB Drive to get some files from it, and he said he couldn't get it to work.
    I know it was working beforehand on my machine which was running Mavericks. But since then I've updated to Yosemite and I learned he was on Yosemtie too.

    I have another 3TB drive and it works both on Yosemite with no issues. I just find it strange my newer drive, the 4tb doesn't work.

    Now when the drive is plugged it I get the following error message "the disk you inserted was not readable by this compute" with three options: initialise, ignore or eject.

    Any help or advice given is greatly appreciated.
  2. crjackson2134 macrumors 601


    Mar 6, 2013
    Charlotte, NC
    I know you have a backup of the data, so just start with trying to reformat (initialize) and see what happens. Hopefully he didn't drop it or something.
  3. Farkle-Mpls macrumors newbie

    Apr 7, 2013
    Minneapolis, MN, USA
    4TB issue

    Careful on that suggestion to reformat your drive! The problem may be elsewhere.

    I have two 4TB Seagate drives and 9 other drives. Post Yosemite upgrade, all 9 disks mounted but the only two 4TB disks I have both fail to mount.

    I have rebooted a dozen times with different combinations of disks. When I strip every external USB device off my Mac and plug the 4TB Seagate into the builtin USB, it will eventually hang, then crash, the Mac before Finder is completely loaded. It happens the same with the other drive too.

    I don't think it's a drive issue so reformatting may not be the next logical step. I'm going to find a pre-Yosemite Mac and see if the 4TB disks mount there first, then I will continue my problem resolution process. I'd suggest you do some more research before doing anything destructive to the data on the disks.

    Also, I'm not sure I'd be able to even format the disk as it hangs and reboots the Mac ... you situation does sound different in that regard as at least you get to Finder recognizing the device although not the file system or partition table.

    Lastly, Disk Utility DOES see the disk briefly before the crash so it does survive a bus scan and SCSI device inquiry.

    Will report back if I discover the culprit.

  4. Farkle-Mpls macrumors newbie

    Apr 7, 2013
    Minneapolis, MN, USA
    Follow up: Both 4TB disks which crash my Mac will mount successfully on a pre-Yosemite Mac. Data appears intact as well although I didn't have time to run a thorough FS check via Disk Utility.

    Came home and plugged the 4TB disk back into my Yosemite Mac. Disk Utility saw the disk and it mounted to Finder -- for about a minute. Mouse pointer stopped moving, system crashed with a register dump and rebooted.

    So ... no resolution yet. Ideas welcome. My Mac is hardware version "Late 2007" iMac, BTW, which is supported on Yosemite.
  5. Rob-1 macrumors newbie


    Apr 19, 2015
    Had the following experience, somewhat similar

    Several 4 TB disks and one 3 TB disk were ok on a Mavericks Mac, disks via an external USB enclosure (Sharkoon)
    No problems with 2 TB disks, but big problems with the 3 and 4 TB disks, like described

    On a new Mac
    The 3 or 4 TB disks were not correct recognised on another Mac, with new installed Yosemite from scratch
    I think the following was the root cause

    The USB enclosure (Sharkoon) supports till 2 TB disks, on Mavericks it was more tolerant it seems with 3 and 4 TB disks
    On Yosemite they were unusable

    I bought a new USB enclosure which supports till 6 TB disks (Mediasonic ProBox)
    No problems at all
    All disks correct recognised, correct size

    Hope this helps

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