Really strange problem - COM is always showing. WTF?

So a friend of mine decided to start working with arduino. Today he told me he can't upload the code to the arduino board so I connected to his PC and i saw the problem. No matter what he does, COM1 always appears in the ports list. Even if his arduino is not plugged. If he selects the COM1 port and try to upload a code, the "error uploading to board" appears. So what could cause this?

COM1 is usually not the Arduino. Your friend has it, I have it on one of my machines as well (no idea what it is, it has been there from the beginning).

When plugging/unplugging, there should be a change. If not, drivers are installed incorrectly or are missing. Check in device manager what happens when connecting/disconnecting.

The computer may be using COM1 for another purpose unrelated to the Arduino. The Tools > Port menu lists all ports, not only the ones created by plugging in an Arduino.

Possible causes of a port not appearing when you plug in an Arduino:

  • You need to install the correct driver for the USB-serial chip on the Arduino. Check which chip is used on the board and find and install the correct driver.
  • You are using a charge only or defective USB cable. Verify that the cable works for data on another device.
  • You have the USB cable plugged into a USB 3.0 port on the computer. Use a USB 2.0 port instead.