Mike Richards2
Level 1 (90 points)
Notebooks

Q: MacBook Retina can't find USB hard disk when it is plugged in again

Hi everyone,

 

I have one of the 2015 MacBook Retina machines and a WD Elements USB3 hard disk that I use as a Time Machine backup when travelling. The disk is plugged into the USB-C through one of the Apple dongles and when I first boot the machine, the USB drive is mounted and appears on the Desktop. It does everything just fine.

 

When I want to take the machine away, I eject the disk, wait for the safe message and then physically unplug the drive. However, when I come back and plug in the drive again, the Mac doesn't see it. Power is going to the drive as the light comes on and I can hear it spinning. It just doesn't mount and is completely invisible to MacOS.

 

I've checked all the connections, even used another dongle - no luck. Logging out doesn't fix it, and I've tried resetting the NVRAM. So far the only fix is to reboot the Mac whereupon the drive reappears - at least until I need to unplug it again.

 

Anyone got any ideas what is going on and if there is a fix?

 

Many thanks,

 

Mike.

MacBook (Retina, 12-inch, Early 2015), OS X El Capitan (10.11.6)

Posted on Aug 30, 2016 8:43 AM

by flyonsnow,Solvedanswer
flyonsnow flyonsnow
Level 1 (14 points)
Notebooks
A:

Hello Mike,

    I have tried several times with my Macbook and found the possible reason that caused the problem.

    Macbook (2015, OS X El Capitan 10.11.6)  + Apple multiport adapter + 2T usb disk + 64G flash disk (usb + usb-C ports)

 

   1. If the 2T usb disk can not be found when re-plugged into the adapter,  the 64G flash disk can not be found (even using the usb-c port to connect with Macbook directly).  --- Reboot is the only way  .....

 

   2. When the Apple multiport adapter connected with Macbook WITHOUT recharging, the usb disk and flash disk both work well, the Macbook can re-find the disk after sleeping more than 3 hours.

 

   3. When recharging the Macbook through the multiport adapter, I plugged in the usb disk and then unmounted. After closing the Macbook for 3 minutes,  the problem appeared --- the usb disk can NOT be found again!

 

  Thus, for my Macbook, the problem seemed due to the power distribution in the adapter, and the solution now is (1) when using the usb disk, do not recharge the Macbook; Or (2) plugging in the usb disk first and then connecting with the power.

 

Best

John

Posted on Sep 6, 2016 8:47 AM

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Mike Richards2

Q: MacBook Retina can't find USB hard disk when it is plugged in again

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  • Helpful answers

  • by jeremy_v,

    jeremy_v jeremy_v Aug 31, 2016 11:22 AM in response to Mike Richards2
    Community Specialists
    Aug 31, 2016 11:22 AM in response to Mike Richards2

    Hello Mike Richards2,

     

    Thank you for using the Apple Support Communities!

     

    It is my understanding you are not able to see an external hard drive once it is ejected and then plugged back into the computer.  I have a couple suggestions that hopefully will help you.

     

    It is important to try to isolate what is causing this to happen.  The first thing to do to help isolate what is causing the problem is to start the computer in what is called Safe Mode and see if the problem still occurs.  

     

    Starting up in safe mode:

    1. Choose Apple menu > Shut Down.
    2. After your Mac shuts down, wait 10 seconds, then press the power button.
    3. Immediately after you hear the startup tone, hold down the Shift key.
      You should press the Shift key as soon as possible after you hear the startup tone, but not before.
    4. Release the Shift key when you see the gray Apple logo and progress indicator.

    ​OS X El Capitan: Start up in safe mode

     

    Once the computer is running in safe mode, see if you can duplicate the issue.  If the issue does not appear, go ahead and try restarting normally again.  If the issue is gone, it may have been caused by a cache file or directory issue that starting in safe mode fixed.

     

    If the issue returns, you are going to want to check login items.  Follow these instructions to remove the login items:

    OS X El Capitan: If you think you have incompatible login items

     

    Remove the login items, restart the computer, and see if the issue continues.

     

    Have a great day!

  • by Uncle_Badger,

    Uncle_Badger Uncle_Badger Sep 2, 2016 3:23 AM in response to Mike Richards2
    Level 1 (12 points)
    Mac OS X
    Sep 2, 2016 3:23 AM in response to Mike Richards2

    Can you see it in Disk Utility?

     

    Have you tried plugging it in to an alternative computer?

  • by Mike Richards2,

    Mike Richards2 Mike Richards2 Sep 2, 2016 8:17 AM in response to jeremy_v
    Level 1 (90 points)
    Notebooks
    Sep 2, 2016 8:17 AM in response to jeremy_v

    Hi Jeremy,

     

    Thanks for the email. I tried the safe boot and removing all the log in items and had about 24 hours where the disk mounted just fine each time. However, I just tried it again after the machine had slept for a few hours and the disk does not mount at all.

     

    I'm wondering if this could be an issue with the Apple multiway adaptor I use to charge the machine and connect to peripherals. A friend sent me this tweet from Matt Gemmell:

     

    https://twitter.com/mattgemmell/status/770949208983662593

     

    “The new MacBook seems to have also fixed the issue I had with the USB-C multi-adapter failing to mount a hard drive 9 out of 10 times.”

     

    I'm wondering now if it is the multi-adaptor which is the root of the problem as a no-brand USB-C to USB/Ethernet hub works every time. But I can't charge with that. Anyone know if there have been any quality control issues with Apple's own HDMI/USB/USB-C multi adaptor?

     

    Thanks,

     

    Mike.

  • by Mike Richards2,

    Mike Richards2 Mike Richards2 Sep 2, 2016 8:19 AM in response to Uncle_Badger
    Level 1 (90 points)
    Notebooks
    Sep 2, 2016 8:19 AM in response to Uncle_Badger

    Hi,

     

    Thanks for the suggestion. Neither Disk Utility nor the command line can see the disk. The drive also doesn't do that little stutter-start up when I plug it in.

     

    I've tried it with a 2011 iMac and it worked just fine.

     

    So it looks like it is either the MacBook or the adaptors which are the cause of the problem.

     

    Thanks again,

     

    Mike.

  • by flyonsnow,

    flyonsnow flyonsnow Sep 5, 2016 8:27 AM in response to Mike Richards2
    Level 1 (14 points)
    Notebooks
    Sep 5, 2016 8:27 AM in response to Mike Richards2

    Hello Mike,

         Have you fixed this problem?

         My macbook has this problem recently, but it worked well before. I have tried the apple usb-c to usb adapter and USB-C multi-adapter, both failed 9 out of 10 times when the disk replugged. Only the reboot can solve the problem, and works well until the computer recovers from slept.

       Any suggestions?

  • by Mike Richards2,

    Mike Richards2 Mike Richards2 Sep 5, 2016 12:17 PM in response to flyonsnow
    Level 1 (90 points)
    Notebooks
    Sep 5, 2016 12:17 PM in response to flyonsnow

    Hi,

     

    Sorry, no progress apart from I'm sure it is not the disk that is to blame. At the same time, the adaptor works fine with USB memory sticks, so I'm guessing there is something about the adaptor or the MacBook which is at fault. I've just tried an Apple USB-C to USB adaptor and that has the same problem. As I mentioned above, the cheap Chinese Ethernet/USB adaptor works fine every time.

     

    By the sounds of it we're both seeing the same issue and it is something to do with the machine going to sleep or ejecting the disk that is to blame.

     

    One thought. My external drive pulls power through USB, and I don't have a USB disk that draws power from a separate adaptor to see if it is a power related problem. Any chance you do?

     

    I might have to make a visit to the Apple Genius Bar next time I'm near an Apple Store - only the fourth visit with this machine.

     

    Mike.

  • by flyonsnow,

    flyonsnow flyonsnow Sep 5, 2016 5:53 PM in response to Mike Richards2
    Level 1 (14 points)
    Notebooks
    Sep 5, 2016 5:53 PM in response to Mike Richards2

    Hi Mike,

        Thank you for your response. I have tried:

        1. update my paragon NTFS version, it fixed the some problem of my 2T usb disk, but did not solve the problem.

        2. I got a 64G flash disk with type-C port and plugged directly into my macbook (without the USB-C adapter), the problem is still there.

       Both the 2T usb disk and flash disk works well in my macbook pro with the same MacOS (El Capitan).

     

       If you find the solution, please let me know. Thanks a lot!

     

    John

  • by flyonsnow,Solvedanswer

    flyonsnow flyonsnow Sep 6, 2016 8:47 AM in response to Mike Richards2
    Level 1 (14 points)
    Notebooks
    Sep 6, 2016 8:47 AM in response to Mike Richards2

    Hello Mike,

        I have tried several times with my Macbook and found the possible reason that caused the problem.

        Macbook (2015, OS X El Capitan 10.11.6)  + Apple multiport adapter + 2T usb disk + 64G flash disk (usb + usb-C ports)

     

       1. If the 2T usb disk can not be found when re-plugged into the adapter,  the 64G flash disk can not be found (even using the usb-c port to connect with Macbook directly).  --- Reboot is the only way  .....

     

       2. When the Apple multiport adapter connected with Macbook WITHOUT recharging, the usb disk and flash disk both work well, the Macbook can re-find the disk after sleeping more than 3 hours.

     

       3. When recharging the Macbook through the multiport adapter, I plugged in the usb disk and then unmounted. After closing the Macbook for 3 minutes,  the problem appeared --- the usb disk can NOT be found again!

     

      Thus, for my Macbook, the problem seemed due to the power distribution in the adapter, and the solution now is (1) when using the usb disk, do not recharge the Macbook; Or (2) plugging in the usb disk first and then connecting with the power.

     

    Best

    John

  • by Mike Richards2,

    Mike Richards2 Mike Richards2 Sep 6, 2016 8:47 AM in response to flyonsnow
    Level 1 (90 points)
    Notebooks
    Sep 6, 2016 8:47 AM in response to flyonsnow

    Hi John,

     

    By Jove! I think you've cracked it. I see the same pattern here. I don't know why it doesn't work both ways, but you're absolutely right - plug in the drive after sleeping and it works, plug in power and then the drive, not a thing. But at least I can back up now.

     

    Thanks and have a 'helpful' recommendation.

     

    Mike.