USB 3.0 External drive ejecting randomly

Here the situation - please bear with me.
Mac running OS 10.10.5. I bought a 2 TB drive and enclosure from OWC. It seemed to work, except sometimes when it would wake from sleep (which I typically do) and I'd get the "Disk ejected" error notice. So, I swapped the 2 TB disk for the main disk (500GB) in my Mac. Same problem. I've removed the drive from Spotlight and Time Machine. I read on another site the speculation that it had something to do with the enclosure controller. I checked and OWC uses the Jmicron chipset in all their enclosures due to compatabillity issues with the new large format drives and USB. I believe the chipset (or Apple or somebody...) is the culprit. Why? Because after the drive ejects, I can"t just unplug it and replug it. Also, Disk Utility doesn't recognize it. To remount the drive, I have to reboot the system. For now, I just don't put the Mac to sleep.
Does anyone have any insight into other controller chipsets that are available in enclosures?
Thanks, Nick
4 answers Last reply
More about usb external drive ejecting randomly
  1. Hi Nick,

    This is not an uncommon problem. Many pepole find that sleep mode and power saving features of external drives create a serious problem in OSX. What model of external HD are you running?
  2. glamdringfh said:
    Hi Nick,

    This is not an uncommon problem. Many pepole find that sleep mode and power saving features of external drives create a serious problem in OSX. What model of external HD are you running?


    Originally, it was a 2 TB, then I swapped it out for a 500 GB. I believe both were Toshiba. I'm reasonably certain it's not the hard drive. Pretty sure it's the chipset in the enclosure.
  3. Bump
    So, does anybody have any info about different chipsets in enclosures?
  4. As I previously said (see: http://www.tomshardware.co.uk/answers/id-3097235/external-usb3-hard-drives-greater-3tb-randomly-ejected-yosemite.html?577699a8e3e90=reload), it seems that new generation imacs with Yosemite or El Capitan often and randomly expel single external hard disks greater than 3tb mounted on USB3 boxes.
    If you want to be aware of this problem you can search the web in different languages. In various forums many senior and corporate users of the last generation macs are, to say the least, disgusted by the persistence of this problem for at least two years. This creates a multitude of problems for those who use new generation USB3 iMacs for working. I've personally tried different hard drives (greater than 3tb on external USB3 boxes) on different iMacs getting the same problem on all new generation iMacs with USB3, retina and Yosemite and no problem on the old type with USB2 iMacs. Particularly a portable USB3 4TB External Drive (Samsung P3 2.5 ") works perfectly and always without ever being expelled on an old iMac that still has the USB2 ports. Instead it is regularly expelled after some time on next-generation retina iMacs with Yosemite and USB3. This happens if I directly connect the disk to the new generation retina iMacs with USB3 ports or if I connect it with a powered USB3 hub. I tried to perform various formatting (both NTSC and Mac) but the problem is still occurring. I also disabled the Spotlight access to disc, energy saving etc.. but the problem persists. This problem does not exist with USB3 sticks (we have many, even 250GB with various kinds of formattings).
    Some friends of mine who are using iMacs at work experienced the same thing. It's a shame that Apple does not solve the problem since that persists for a long time. I ask me if we should recourse to a Class Action to force Apple to solve the problem. it's clear that if all these problems persists with iMacs many of us will be forced to give up Apple products.
Ask a new question

Read More

Storage