After we have posted Quick Fix: how to repair USB Not Recognized in Windows 7/8/10, some users wrote to us that they got nothing plugged in the PC and received USB Device Not Recognized like every five seconds in their Windows 7 computer, which is very annoying. To solve the specific problem, we did some research and here’s a list of possible factors and ways to fix it.

Reason 1 Malfunction of mouse, keyboard or other external connection

Many users seem to forget the fact that their mouse and keyboard is also the USB device and if their cables age or parts tear and wear, the message USB Device Not Recognized will keep flashing.

Solution: Plug out all the USB device, change another functional mouse or keyboard and see if it occurs.

Reason 2 System bug or system error that detects a device mistakenly

Solution: In this case, open your System Checker like Neptune SystemCare is the easiest way to check and fix the system error. Neptune SystemCare helps users to check up computer health and fix the problems to optimize and secure the computer.

Reason 3 Something wrong with USB controller settings

Solution: Go to Device Manager and fix it.

1. Right-click on the Start button and choose Device Manager.

2. Expand Universal Serial Bus controllers.

3. Right-click on it and select Properties.

4. Click on Advanced tab, and at the bottom left of the window check the box in front of "Don't tell me about USB errors" and click OK.

More detail steps, go to Quick Fix: how to repair USB Not Recognized in Windows 7/8/10.

Reason 4 Malware or virus attack

Solution: Run your Anti-malware or anti-virus program.