UNO showing up as Unknown Device, MEGA is working

I ordered an Uno on Amazon:

When I try to connect to my computer via USB, it shows up in device manager as Unknown Device. I cannot select a port in the IDE. The ON light and orange LED are on.

When I swap the UNO out for my MEGA (that I have been using for a year), it shows up in COM3 and the port is shown in the IDE.

Anybody know how to get this working?

This is the error message I get when I try to update the driver.

That is one blurry picture LOL
See Item 5 in the second section and then go from item 1 in the last.

Please[/b] READ THIS POST to help you get the best out of the forum.


These steps may also save you some unnecessary time and effort in the forum.

  • Always provide as much detail as possible to your issue it may be important.
  • If applicable provide your SKETCH inside CODE TAGS ( </> ) or a CREATE share link.
  • If applicable provide a schematic even if hand drawn.


  • Check you have a COMMON GROUND where required.
  • Where possible use USB 2.0 ports or a USB 2.0 POWERED HUB to rule out USB 3.0 issues.
  • Try other computers where possible.
  • Try other USB leads where possible.
  • You may not have the correct driver installed. CH340/341 or CP2102
  • There may be a problem with the board check your wiring first.
  • Remove any items connected to pins 0 and 1.


  • Ensure you turn off any additional security / antivirus just to test.
  • There may be a problem with the PC try RESTARTING it.
  • You may be selecting the wrong COM port.
  • Avoid cloud/network based installations where possible OR ensure your Network/Cloud software is RUNNING.
  • Clear your browsers CACHE.
  • Close the IDE before using any other serial programs.
  • Preferably install IDE’s as ADMINISTRATOR or your OS equivalent

Performing the above actions may help resolve your problem without further help.


Not sure why the image is blurry. It's perfectly fine on mine.
Here is another attempt: error — ImgBB

It is none of these issues, the port and computer work with my MEGA but not the UNO.

I downloaded both of those drivers and I still am receiving the same issue.

Just in case the image is blurry again, I will describe the steps I have taken:

Device Manager (UNO shows up as Unknown Device)
Right click and update drivers

  1. Click Search online automatically for drivers

Error message: Windows found drivers for your device but encountered an error while attempting to install them:

  1. Browse my computer for drivers
    Let me pick from a list of available drivers
    USB Devices -> ATmega16u2 driver shows up
    Click Next

Error message: Windows found drivers for your device but encountered an error while attempting to install them:

What version of Windows as sometimes win 10 can cause its own issues ?

When the driver shows up what was the location on the computer ?
It should be in the DRIVERS folder section of the Arduino install folder.
You should not need to do the search online as a location was added when you install the IDE.
You have installed the IDE I presume ?

A decent pic of the smaller IC near the USB port for each board may also be useful
But post them here as many people will not go visit some random link.

The 16u2 is also prone to damage if the power rails are abused in any way but I doubt that is the case here.
if Windows device manager only sees the 16u2 sometimes that indicates a board without bootloader but that in itself should not stop a driver install.

This is driver folder in the IDE installation.
You should initiate the DPINST (x86 or x64 as needed) as administrator