External USB Hard Drive Not Mounting in Sierra

Discussion in 'macOS Sierra (10.12)' started by Huntn, Jul 21, 2017.

  1. Huntn macrumors G5

    Huntn

    Joined:
    May 5, 2008
    Location:
    The Misty Mountains
    #1
    Frequently when I call it a night, I unmount my external USB drive, turn it off and put my MBP to sleep. Frequently I find that my USB hard drive when turned back on does not mount and sometimes I can see it in Disk Utility and sometimes not. When I can see it if I select the drive and hit the "mount" button, nothing happens. Of note this drive has 2 partitions.

    Is this a known issue?
    What is the solution? Thanks!
     
  2. Taz Mangus macrumors 68040

    Taz Mangus

    Joined:
    Mar 10, 2011
    #2
    Is this on the 2017 MBP? It could be the drive enclosure. I suggest that you try different USB C ports and see if they all act the same. As a sanity check, try out a different drive enclosure on the computer and see if it acts the same. When all else fails, a call to AppleCare might be in order.
     
  3. Huntn thread starter macrumors G5

    Huntn

    Joined:
    May 5, 2008
    Location:
    The Misty Mountains
    #3
    Oct 2016 MBP. Thanks.
     
  4. lexvo macrumors 65816

    Joined:
    Nov 11, 2009
    Location:
    The Netherlands
    #4
    Is there a reason you unmount the drive? I always let my iMac go to sleep with the drives mounted.
     

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