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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?

Stefan Müller
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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 '21 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 '21 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 '22 at 10:13

2 Answers2

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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
pnomolos
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Jacob Vanus
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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 '18 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. – Jacob Vanus Apr 30 '18 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 04 '19 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 '19 at 01:28
  • it would be a good idea to define it as an alias in your profile script. i.e alias resetusb='sudo launchctl stop com.apple.usbd; sudo launchctl start com.apple.usbd' – yerlilbilgin May 15 '19 at 07:46
  • This worked greatly for me. And Apple: seriously? Ever heard of a "refresh" button? Smh. – Luca Fagioli Aug 30 '20 at 10:32
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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 '21 at 15:41
  • @hepcat72 did you ever find a solution to devices connected to USB C without physically unplugging and plugging back in? – Rob Mar 02 '21 at 17:11
  • @Rob - I did not, technically. However, something I did stopped the problem from happening and I'm not sure what it was that brought that about. System update? Monitor setting? System pref setting? Behavior in using the monitor buttons? Wire change? It's been too long ago for me to know what made the difference. – hepcat72 Mar 02 '21 at 17:18
  • @hepcat72 thanks, i ended up replacing my usb hub and all fine now. I guess not all usb c hubs are made equal. New one is by Anker. – Rob Mar 29 '21 at 19:06
  • works for me. Apple should have a button for it. – bronze man Feb 10 '22 at 05:04
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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.

nohillside
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peter
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