How to "restart/repair" an USB port?
None of the answers quite answer the title question.
How to “restart/repair” a USB port?
There are three ways to "restart" a particular USB port:
- Reboot the computer. Or ...
- Unplug, then re-plug, the physical device connected to the port. Or ...
- Disable, then re-enable, the USB Root Hub device that the port is attached to.
In Windows you'd do (3) through the Device Manager or via the devcon.exe utility.
The reason these are the only methods is due to the USB handshaking protocol, which is initiated by the USB device when it's plugged in, not by the controller. This causes problems like being unable to remount a USB flash drive after you've Safely Removed it. But cycling the USB Root Hub device causes all the devices attached to that hub to reinitialize themselves. (The unfortunate side effect is that it causes all devices attached to that hub to reinitialize themselves, which could be problematic if you have other devices on that hub which are in use.)
You should look at NIRSOFT's USB Device view (http://www.nirsoft.net/utils/usb_devices_view.html). I have used this to fix a system that had a disconnected U3 USB drive still mounted preventing anything else in the port being recognized.
I had issues with Windows 7 dropping the USB mouse driver and reinstalling the mouse driver (most of the time) which was annoying as hell.
I tried all kinds of things to fix the problem, driver updates, clean boots, tech support phone calls, Internet software voodoo, but in the end I only had to reset my USB ports.
I did this by turning the computer off, unplugging all USB devices, removing the laptop battery and AC power supply, and finally holding down the power button for 30 seconds.
This fixed a problem that I must have spent at least 20 hours trying to fix; give it a try.