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Question: High sierra USB problems

High Sierra (10.13.1 and 10.13.2). I'm experiencing several problems with USB on two different iMacs.

1. USB hard drives unmount unexpectedly, mostly in the night (Put hard disks to sleep option is not ticked). This generally interrupts Time Machine. Although the drive is mounted in the morning, there are messages that have told me not to remove the drive, even though nobody has.

2. EyeTV DTT Stick, which is a USB device: the EyeTV program freezes. Removing the stick and plugging it back in often fixes the problem. Otherwise, need to reboot.

3. Often receive the message "USB Devices disabled", saying that some USB device(s) is using too much power. This never happened with OSX versions prior to 10.13. Usually three devices connected: EyeTV, iPhone and Toshiba 1Tb USB drive.

I have no solution, but the question is, is anybody else experiencing USB-like problems?

iMac (Retina 5K, 27-inch, 2017), macOS High Sierra (10.13.2)

Posted on


Dec 11, 2017 2:13 AM in response to gnason In response to gnason

I've been having USB disconnected improperly lately too on 10.13.1, turning off 'Put hard disks to sleep' fixed it for me.

Maybe try rebooting your iMac and holding down the 'Shift' key when you hear the chime to run in safe mode.

When you see the login window reboot normally, see if that makes a difference.

Do you use a USB hub?

Dec 11, 2017 2:13 AM

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Dec 11, 2017 5:21 AM in response to munkymajik In response to munkymajik


Thanks v. much for your quick reply.

I do not have "Put hard disks to sleep" ticked, so that doesn't appear to be the issue.

Both iMacs have had their SMC reset, PROM reset, Booted into Safe Mode, DIsk Utility checked Fusion Drives, but problem seems to persist.

The newer iMac does not chime when rebooted. This is, apparently, a feature of newer iMacs. In my experience this is definitely not a good thing. When your Mac is misbehaving you do not want to waste time wondering whether you've hit the right key combination at the right time, and you need some positive feedback for when it is beginning/ending it's boot-up sequence. Enabling Boot-to-Safe mode from the GUI before restarting would also be helpful. You used to be able to boot to recovery disk from the GUI and something similar to booting to safe mode would be helpful too.

I don't use a hub on either machine.

Thanks again. It helps to know that others have seen this.

Dec 11, 2017 5:21 AM

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Question: High sierra USB problems