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I have a MacBook Pro and work with different external monitors. The monitors have a keyboard and a mouse attached. Frequently the MacBook does not recognize the USB devices in the display and the keyboard and mouse do not function. I have to reboot. Is there a way to reset the USB system without rebooting?

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  • Similar issue here with a Dell P2721Q Dell monitor and a Macbook Air connected via USB-C. Does the display itself connect and show your desktop? Mine does, but the connected USB devices do not function.
    – hepcat72
    Jan 21, 2021 at 15:44
  • I've had the same problem when connecting/disconnecting my monitor. The launchctl commands below didn't work for me, but turning my monitor off and then back on did work (leaving as a comment as I don't have any rep points to answer).
    – user167019
    Sep 13, 2021 at 18:07
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    For those trying to do this with a USB hub: check out uhubctl, a program that lets you toggle ports on supported USB hubs. From this answer
    – Sentinent
    Feb 11, 2022 at 10:13

2 Answers 2

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You could try restarting the usb daemon in terminal. Like so:

sudo launchctl stop com.apple.usbd; sudo launchctl start com.apple.usbd
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    You might want to put that into a script. If you disable USB, then your keyboard/mouse will stop working as they are USB devices.
    – Allan
    Apr 30, 2018 at 18:16
  • @Allan I actually tested and the devices continue to function. Still a script or Automator action with a keyboard shortcut would make it a lot easier to use if it works. Apr 30, 2018 at 18:21
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    Wow! My USB to Serial adapters keep freaking out the usb ports until I run out of them and have to restart my mac. This solution worked, I don't have to do restarts any more because of this nonsense!
    – Raidok
    Jan 4, 2019 at 20:38
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    Alas this does not seem to do anything - no longer connected devices are still reported as present, and newly connected devices do not enumerate.
    – user221106
    Feb 16, 2019 at 1:28
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    Doesn't work for me, though I did get USB to work by unplugging the USB-C, (running the above commands - though I'm not sure that was necessary), and re-plugging. I.e. I didn't need to reboot. Still, would be great to have a solution that doesn't require messing with wires.
    – hepcat72
    Jan 21, 2021 at 15:41
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Same problem here, it happens with a thunderbolt Apple display, and a thunderbolt LG display, and it's sometimes fixed after connecting/reconnecting/changing USB ports for the keyboard. On the LG even that did not work, only a complete reboot. I'm googling now for a USB reset solution that does not reboot my Mac.

Found this tool here: http://v6download.touch-base.com/downloads/MacProber/USB_Prober_Mac_OS_X_10.7.3.zip. Still works on Sierra. I will keep this handy on my desktop in case it happens again.

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