PC Doesn't Fine Uno Driver

I have a PC that is connected to a Mega and an Uno but the PC can't find a driver for the Uno.
The Mega is on Comm8, the Uno on Comm5. Aren't the drivers part of the IDE? I'm running version 1.8.16 with Win7. The Mega functions just fine but I can't upload to the Uno. Seems very odd.

The PC isn't connected to the Internet. What are my options to fix this?


How do you know what ports they are on? Did you refresh the ports list after plugging it in?

If I look at the device manager, the Mega is on Com8, and works fine, the Uno is on Com5, but the device manager doesn't know what the device is and can't find a driver. Yes, I refreshed the ports; shut everything down and re-booted.

Thanks for replying.

Is it a clone UNO or genuine?

I'm a little confused. As far as I know, you will not see a COM port if the device is not recognised. So COM5 is more than likely not your Uno.

If your Uno does not use the 16U2 TTL-to-USB converter, the board will not be recognised as an Arduino Uno but as a serial device.

In below image, a genuine Uno with 16U2 is on COM8, a SparkFun RedBoard with a FT232 is on COM5 and a clone Nano with CH340 chip is on COM10.


Not always for clone boards. Arduino does not produce boards with CH340 so they don't supply the driver for that.

You're correct in that the device manager did not see the Uno, it designated the device on com5 as unknown; if I unplug the Uno, there is no com5 displayed in the device manager.
Let me get back to you tomorrow; the computer in question is at "work". I will print out the device manager com assignments with and without the Uno plugged into the PC. I don't use clones; the Arduino Uno is a genuine part.

Obviously, I don't know much about this topic.  I'll supply more information tomorrow.  Thanks for staying with me on this.


Check for any changes anywhere else in the device manager as well.

Also try to find the VID and the PID of the board.

  1. Right click the device in device manager, select properties.
  2. Tab page details, from the dropdown, select Hardware Ids.

O.K. Here's what I tried today (I realize some of this may be irrelevant).

  1. Boot up mini-ITX with only Mega attached
    Device Manager, Under Ports
    Communication Port (Com1)
    Communication Port (Com2)
    Printer Port (LP!)
    USB Serial CH340 (Com8)

  2. Add Uno and Restart mini-ITX
    Device Manager Under Ports - unchanged
    New Menu Item - Other Devices
    Under Other Devices - Com5 with a yellow icon of an exclamation point
    Right click on Com5 - Properties/Details, two lines

Both Arduinos are genuine.


Gentlemen and gentlewomen,

The problem was fixed by re-installing the drivers.

Sorry for the needless confusion and thanks for the help.


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