USB 3 disconnects on Mac

Discussion in 'Mac Basics and Help' started by unplugme71, Sep 8, 2015.

  1. unplugme71 macrumors 68030

    May 20, 2011
    I've been having this issue since USB 3 pretty much first came out. My 2012 and 2014 Mac Mini's both experience frequent USB 3 drive disk ejections.

    It doesn't matter if my computer is on or sleeping, the drive will eventually eject - it could be 15-20 minutes or 8-10 hours. It seems to happen randomly and sometimes will be fine for an entire day or more. The external drive has its own power supply that I use. When I notice the ejects, the drive seems to remain powered on. I've replaced the USB 3 cable. I've tried different ports. Clean install of OS X 10.9, 10.10, etc.

    I need an external drive connected as my iTunes library is on there so I can stream content to Apple TV.

    I disabled putting drives to sleep in System Preferences as well hoping that would fix it.

    Any idea what's going on? What else can I try? I've even left it without iTunes running to see if it was iTunes doing something.

    At this point, I'd like to switch over and give TB a try except it seems to be a very pricey alternative and not many "BYOD" options out there. I prefer RAID 1, but a single drive wouldn't be bad as long as I can store 2TB on it.
  2. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle
    I've got a box. It's a really big box. And, it's full of cables. Cables that were in a box with the thing I wanted...

    I own - personally and through my company - several 2012 Mini Servers, and I've got one on my desk. I own - also, personally and through my company - plenty of external storage that utilizes eSATA, FW800, USB 3, and TB1 - with all of it having multiple interfaces. Gotta get that out of the way.

    When I took the plunge with my first Mini, I read about what you're describing but going back to FW400, so this isn't new. There's a lot of threads about what could be the root cause - ports, buses, cables, SW bugs. I'm leaning toward cabling. I have two drives that shipped with insulated cabling - a Drobo NAS and a Buffalo Workstation - if I use those cables, my transfers are good; if I use the cheap cabling that came with the other drives I get those disconnection error messages.

    For FW, I have an old G-TECH G-RAID drive with eSATA / FW400/800 / USB2 - the insulated FW cables that shipped with that drive are insulated. It's hooked up to the Mini Server on my desk.

    For USB3, I have several drives for transferring data to/from. If I use the cheap cables - thin, obviously not insulated - I get the same dropouts you're experiencing. I've transferred about 1TB in the past few weeks to/from my Mini Server while using a quality, insulated cable with one disconnection notice (which I'm not happy about but it's better than others have whined about - me included!).

    As for TB? Some of my drives have TB and USB interfaces. I have zero ( 0 ) issues with TB file transfers with my Minis, going back about 3 years. Not. One. Failure. I can pay $50 to $100 more for a drive with TB, but my contractors standing around will cost my clients at least $1500 per hour - I review and approve billing statements, and I'm not embellishing.

    My advice is to get a decent shielded/insulated USB3 cable or consider TB 1/2 or Gigabit Ethernet as an option. While you're not dealing with the field/client costs that I have to deal with, consider the cost of therapy! :p

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