I have an Arduino Uno (Uno R3 clone from Elegoo) that I can't connect to the Arduino IDE anymore (it used to connect fine and the program on it still runs) on two separate computers (both Windows 10). What's odd is I have another Uno clone that connects fine. I tried the loopback test but I don't get a device-insertion tone and the serial monitor gives me an error that it can't start monitoring. I check the Windows Device Manager and it didn't show anything under "Ports (COM & LPT)" so I tried installing it by "Add Legacy Hardware" but I get the error "This device cannot start. (Code 10)
The specified request is not a valid operation for the target device."
It certainly looks like one of the better clones with a real Atmel chip for the USB.
Only problem is those chips are prone to breakage or bootloader failure on occasion.
Quite often if that is the only issue they can still be either risen from the dead by using another working board to replace the bootloader or still programmed via the ICSP if the smaller atmel is dead.