HT205750: About the OS X El Capitan v10.11.4 Update

Learn about About the OS X El Capitan v10.11.4 Update
jake969
Level 1 (5 points)
Desktops

Q: v10.11.4 my USB external hard drive disconnects after update

After this update OS X El Capitan v10.11.4 my USB external hard drive disconnects. Never occurred prior to the update. Now ever time the monitor goes to sleep the drive disconnects. Not power settings to alter this behavior. Has this happened to anyone else? Easy fix?

 

I noticed in the update notes there were several fixes for USB issues. Seems this update caused another one.

Mac Pro, OS X El Capitan (10.11.4)

Posted on Apr 19, 2016 11:09 AM

by lllaass,Apple recommended
lllaass lllaass
Level 10 (189,400 points)
Desktops
A:

- Try resetting the SMC and NVRAM/PRAM

Intel-based Macs: Resetting the System Management Controller (SMC)

About NVRAM and PRAM       

Posted on Apr 19, 2016 12:23 PM

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jake969

Q: v10.11.4 my USB external hard drive disconnects after update

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  • by lllaass,Apple recommended

    lllaass lllaass Apr 19, 2016 12:23 PM in response to jake969
    Level 10 (189,400 points)
    Desktops
    Apr 19, 2016 12:23 PM in response to jake969

    - Try resetting the SMC and NVRAM/PRAM

    Intel-based Macs: Resetting the System Management Controller (SMC)

    About NVRAM and PRAM       

  • by Grant Bennet-Alder,

    Grant Bennet-Alder Grant Bennet-Alder Apr 19, 2016 12:30 PM in response to jake969
    Level 9 (61,073 points)
    Desktops
    Apr 19, 2016 12:30 PM in response to jake969

    Apple is constantly tightening the USB-supplied power, to meet Energy Star and other requirements.

     

    When things sleep, you can expect the USB power to drop as well. If your External Drive cannot survive that power drop, you may need to get it an independent power supply, or use a powered USB Hub.

  • by jake969,

    jake969 jake969 Apr 19, 2016 9:01 PM in response to Grant Bennet-Alder
    Level 1 (5 points)
    Desktops
    Apr 19, 2016 9:01 PM in response to Grant Bennet-Alder

    The drive has it's own power supply, and it never loses power anyway. I get the "this drive was not ejected properly" error and it disappears when the monitor goes to sleep. I've even tried the Amphetamine app- "keep this drive alive" option. I use it as a media server and is required to be active to access remotely. This disconnect occurred only after the OS update. 

  • by jake969,

    jake969 jake969 Apr 19, 2016 9:02 PM in response to lllaass
    Level 1 (5 points)
    Desktops
    Apr 19, 2016 9:02 PM in response to lllaass

    I tried resetting the SMC. We will see if it still occurs throughout the night. Hopefully that will fix it.

  • by Rick Morton1,

    Rick Morton1 Rick Morton1 Jul 20, 2016 2:49 PM in response to jake969
    Level 1 (109 points)
    Video
    Jul 20, 2016 2:49 PM in response to jake969

    I have the same problem, but only with my SanDisk SSD drives. I bought a few of these and the Sabrent 3.0 > Sata cable to connect them via USB. Whenever the computer goes to sleep, it drops the drive and I get the "Improper disconnect" message window. This happens on FOUR different Macs with 4 different SSDs and cables, so it's a system thing... not associated with a bad drive or cable. In fact, they will sometimes drop WITHOUT the computer going to sleep. I'm direct connected; not on a hub. SanDisk actually called me today (after emailing them) to explain that this is NOT a SanDisk problem...it's an Apple system problem. I agree that it sure feels like a power issue, but my regular USB drives don't drop... just the SSDs so there must be a big difference in these. SanDisk reminded me that these are meant to be INTERNAL drives, even though someone can make a cable to use them externally, which is true. It appears there's a system problem that Apple needs to fix. And you can find three or four year old posts with similar problems... so someone is ignoring us! These little SanDisk SSDs are great; fast, cheap, small... I only wish I could use them!