Port can't be found (greyed out) and avrdude: ser_open(): can't open device "\\.\COM8"

Development Tools IDE 1.x
1

Hello,

I am having trouble finding the port for my arduino micro. The problem is that the port ist greyed out, so I can't even choose one. When I upload the script, it says that the upload is complete, but when I open the serial monitor it immediately says that no COM port could be found and the port is greyed out.

Interestingly, when I use a basic script (eg. Blink) it sometimes can find the port, but sometimes it doesn't... In this case it gives me following error message:
avrdude: ser_open(): can't open device "\.\COM8"

I really tried everything I found on the internet. Ive tried:

  • de and reinstalling the device in device manager
  • installing a new driver (CH341) but my computer says after installing that the best driver is already installed
  • changing the cable
  • changing the pc
  • resetting the arduino micro while uploading

I am really frustrated and I would be really thanful for some help!

2

An Arduino Micro does not have a CH340/CH341 so (re-)installing that driver is not very useful :wink:

What does Windows device manager think of your board after an upload when there is no COM port?

Which version of the IDE are you using?

3

I am using IDE 1.8.19

the device manager doesn't show the arduino at "other devices"

And for Ports there are multiple coms shown for arduino micro

4

At the same time? I guess that would be a problem and maybe it's time to clean out the COM stack. I never had to do it myself so can't quite advice.