SC5000 not connecting to computer via usb

ive recently bought 2 sc5000 players and the x1800 mixer, Ive updated the firmware on the mixer to 1.2 and the firmware on both units to 1.3.1. one unit however was unable to update via usb cable as the computer would not recognize the device. the same happens when using controller mode going into serato. One player works fine and the other stays showing the screen “looking for computer” I have tried switching usb cables and using different usb ports on my laptop, as well as tried it on a second laptop, and the same problem is always there with the same player. I’ve even tried using only the one player at a time and the problem still persists. I have only had these players less than one week. I’m starting to think there’s a problem with this specific sc5000 because the other is working 100% fine and i’ve done all the same update processes to it.

What’s your OS? I use Windows 7 and have to update by flash drive.