I did a lot of searching but could not find a solution.
Win7 does not work , But Win10 works ( plug and play.)
My UNO R3 does not connect to usb with Win7.. "unknown device" in device manager.
The USB chip is the original Mega 16U2.
I tried updating driver..pick from list..Arduino/drivers..ERROR COULD NOT UPDATE.
Search pc and internet ..NO driver found.
Was this issue ever resolved for Win7 with the Mega16U2 chip.(UNO R3)
There must be thousands of Aduino users with Win7 and the UNO is very popular so the UNO R3 cannot be used on Win7??
There seems to be a missing file ..Arduino UNO.inf , I searched my pc but could not find it.(Win7).
Thanks for any advice.