Hard Drive Unexpectedly Disconnects

Discussion in 'Mac Basics and Help' started by mrbobdobolina, Nov 30, 2018.

  1. mrbobdobolina macrumors member


    Feb 28, 2016
    Hi all. I need advice.

    Last fall I purchased a 4-Bay drive enclosure from OWC. A Thunderbay with Thunderbolt 2. I ran it almost a year without any problems. A few months ago they had a sale on the updated product with Thunderbolt 3. Since my 2017 iMac has TB3 ports, I decided to buy a new model.

    I have the enclosure setup as 4 independent drives, each for a different purpose. Everything was fine for two weeks, then one of the drives Unexpectedly disconnected. I looked in Disk Utility and it didn't show up any longer. However, the other three drives were just fine. A few days later it happened again. Different drive.

    After a few weeks of this nonsense and after going back and forth with OWC Tech Support, I sent it back. They held onto the unity for 3 weeks and shipped it back to me. Apparently they ran it for a few days and then replaced the logic board.

    Now that I have it back, one of the drives keeps disappearing every couple days. I can't just remount the drive because it doesn't show up anywhere. I either have to power down the unit or remove and reinsert the drive. It's only the single drive that goes away. (And that drive is fairly new.)

    I've tried changing the Thunderbolt port I'm using, but that doesn't seem to help. I could try switching the drive order around, but that didn't help when I sent it back the first time.

    When I contacted OWC about it they told me to install SoftRAID because that would monitor the drive, but none of the drives are giving me errors or failing their SMART status.

    I am using a 2 meter Thunderbolt cable, because that's the length I need to put the enclosure on the lower shelf of my desk.

    Do I buy a new cable to see if that changes things? (If so, how do I ensure I get a good one?)

    Do I sent my enclosure back to OWC? (And get a refund? And buy an older version?)

    Do I take the time to move all my drives back to the old enclosure and see what happens? (And do I buy a TB2 to TB3 adapter so I can plug the enclosure into my dying 2011 iMac to see what happens?)

    I use these drives for work and the idea that they'll just drop out on me in the middle of a project is terrifying, but at the same time, I don't want to chase my tail moving drives between enclosures when I could be getting actual work done. (Yeah, that sounds lame now that I type it out.)

    Any other things I could try to diagnose the problem? Is it an issue with my iMac?

    Any advice is appreciated. Thanks much.

    - Your Friendly Neighborhood Philip
  2. wlossw macrumors 65816


    May 9, 2012
    Montreal, Quebec, Canada
    What are the brand, model and capacity of the drives in the enclosure?
  3. mrbobdobolina thread starter macrumors member


    Feb 28, 2016
    6 TB Toshiba X300
    4 TB Seagate (2.5 inch) Backup Plus
    4 TB Seagate BarraCuda (3.5 inch)
    2 TB WD Black

    The 3.5 inch 4TB BarraCuda is the one currently dropping off.

    Could it be that the drive is going to sleep?
  4. HDFan macrumors 65816

    Jun 30, 2007
    I assume that in System Preferences/Energy Saver "Put hard disks to sleep when possible" is not checked?

    I had an OWC thunderbolt dock and another vendors 5 bay USB 3 enclosure setup as a JBOD which both kept doing unexpected ejects. Both were replaced but problem of attached drives ejecting did not go away. Ditched both, bought a different enclosure (OWC Thunderbay 4 Bay) and problems went away. So my experience has been that it is an enclosure issue which seemed to be integral to their design.
  5. wlossw macrumors 65816


    May 9, 2012
    Montreal, Quebec, Canada
    Ok well let me start off by saying that Seagate barracuda drives have suffered from a very high failure rate. In my experience using drives designed for nas or raid is the best choice for any external enclosure with more than 1 drive in it. I had a similar problem
    With disks ejecting when I was using consumer drives in my enclosure. Switching to wd red drives solved my problem.

    In your case specifically I would suspect the Seagate is becoming unreliable. Try replacing it with another drive if possible.

    This article summarized some of the many problems with that series of drives:
  6. mrbobdobolina thread starter macrumors member


    Feb 28, 2016
    This is good info. I'll look into it. Thank you.

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5 November 30, 2018