USB Device Not Recognised
A USB device (drive, mouse, keyboard, printer or similar) either isn't detected at all, shows an "unrecognised device" message, or worked before and has now stopped.
Quick answer: This can be the device, the cable, the specific port, or a Windows driver issue — trying the same device in a different port is the fastest way to narrow it down. If nothing works in any port, the issue is more likely Windows or the device than the computer's USB hardware broadly.
Likely causes
- A faulty cable or the device itself has failed
- A specific USB port has failed or lost power, while others still work
- A driver conflict, often after a Windows update
- USB power management settings turning ports off to save power
What you can safely check yourself
- Try the same device in a different USB port to isolate whether it's the port or the device
- Try a different, known-working device in the same port
- Restart the computer, which resolves a surprising number of one-off USB glitches
- Check Device Manager for a yellow warning icon next to any USB entries
When it needs a proper look
If multiple devices fail in the same port but work elsewhere, that port has likely failed and needs a look. If a device fails in every port on every computer you try, the device itself has failed.