External HD (on extended USB cable) disconnects when iMac sleeps.

Discussion in 'Mac Accessories' started by Qwerty11, Nov 16, 2014.

  1. Qwerty11 macrumors regular

    Joined:
    Sep 1, 2010
    #1
    I have a 3TB Backup Plus. It is connected to the iMac via a 15' USB cable -> original USB cable. The 15' USB is one that is supposed to be powered (via the USB) to keep the voltage up for the distance. The issue is everytime I wake the iMac from sleep it says the drive has been improperly disconnected. I'm trying got figure out what I need to do to make this work. Any ideas?
     
  2. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #2
    You could try it with the drive directly connected to the computer without the long cable ... but I would guess that you will have the same problem.

    OS X seems to have a problem with USB 3.0 drives disconnecting with sleep mode, and you will get the improper disconnect message on wake.

    You might try "Jettison" to resolve the problem for now.

    https://itunes.apple.com/us/app/jettison/id447430809?mt=12
     
  3. Qwerty11 thread starter macrumors regular

    Joined:
    Sep 1, 2010
    #3
    Thanks for the link, I will check it out.

    FYI, the drive works fine with it connected to the iMac using only the "regular" USB cord.
     
  4. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #4
    Hmmmm ... strange.

    I get the message too occasionally, but it always seem to reconnect OK without any issues.

    You might also be sure your USB extension cable is USB 3.0 certified and well shielded to avoid bluetooth interference with a mouse or keyboard.
     
  5. Qwerty11 thread starter macrumors regular

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    Sep 1, 2010
  6. Fishrrman macrumors G5

    Fishrrman

    Joined:
    Feb 20, 2009
    #6
    OP wrote above:
    [[ I have a 3TB Backup Plus. It is connected to the iMac via a 15' USB cable -> original USB cable. ]]

    And then added:
    [[ FYI, the drive works fine with it connected to the iMac using only the "regular" USB cord. ]]

    My reply is something akin to the patient saying to the doctor, "doctor, it hurts when I do this"; after which, the doctor replies, "well then, don't DO that."

    Suggestion:
    If it works using the original (i.e. shorter) cable, use that cable.

    Use WHAT WORKS.

    Really, as simple as that...
     
  7. ColdCase, Dec 8, 2014
    Last edited: Dec 9, 2014

    ColdCase macrumors 68030

    Joined:
    Feb 10, 2008
    Location:
    NH
    #7
    I'm going to guess.

    When the MAC sleeps with a USB drive connected, it does not unmount the drive and still knows it is there. When I simply unplug a USB device while the Mac is sleeping, the Mac sometimes wakes up and complains, sometimes it just complains when it wakes up later, similar to the behavior Qwerty11 observed.

    I'm going to guess that when the cable's active circuitry looses power when the Mac sleeps, it cuts the connection and the Mac thinks the cable is unplugged.

    This behavior has been an annoyance to laptop users when they close the lid and then later unplug and run. Usually folks just ignore the warning, but apps like Jetison will unmount external drives before the Mac sleeps and mount them when the Mac wakes up. So one solution would be to unmount (eject) the drive before you put the Mac to sleep. Another would be to install an app, although I'm not sure of Yositime compatibility. Otherwise just ignore the warning. You are lucky you are not trapped in a unable to sleep mode :)

    Now there is no data corruption danger by ignoring the warning as when the Mac is sleeping there is no data in transit.
     
  8. Qwerty11 thread starter macrumors regular

    Joined:
    Sep 1, 2010
    #8
    That would be fine and well if my use case allowed the HD to be connected to the computer by the short cable, but it doesn't, so the doctors suggestion doesn't help me.
     

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