# Port monitor error: command 'open' failed: Invalid serial port. Could not connect to COM serial port

**URL:** <https://forum.arduino.cc/t/port-monitor-error-command-open-failed-invalid-serial-port-could-not-connect-to-com-serial-port/1127713>\
**Category:** Uploading\
**Created:** [May 16, 2023, 7:24pm UTC](https://forum.arduino.cc/t/port-monitor-error-command-open-failed-invalid-serial-port-could-not-connect-to-com-serial-port/1127713 "2023-05-16T19:24:51Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![jakubtan](https://avatars.discourse-cdn.com/v4/letter/j/96bed5/32.png) [@jakubtan](https://forum.arduino.cc/u/jakubtan)\
**Post date:** [May 17, 2023, 10:01am UTC](https://forum.arduino.cc/t/port-monitor-error-command-open-failed-invalid-serial-port-could-not-connect-to-com-serial-port/1127713/5 "2023-05-17T10:01:59Z")

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Yes, when I disconnect the board the ports disappear but it should disappear when nothing is connected, right?

I am using clone with CH340. Although there is nothing written on the component the driver says CH340.

I also tried to use old computer with Windows 10 and everything works. Computer recognise the COM port, can connect and I am able to upload. So it is something with the computer but I don't really know. I am using Windows 11.

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