Port greyed out on the Tools menu in 4.2.0 and 4.4.0 - IDE 1.8.19, Windows 7

[Andy2No]

Possibly this only applies to Windows 7, or some other specific set of circumstances I have but others don't.

I no longer get the option to specify a COM port on the tools menu in Arduino IDE 1.8.19 for the Pi Pico, or for the Pi Pico 2. I initially upgraded to use the Pico 2, which has a possibly unique set of problems with Windows 7, though others seem to have similar problems, perhaps just with Windows 11. That's a bit too complicated to go into for now, but in involves having to delete the removable device (.uf2) driver to get the COM port one to appear, and vice versa. This is simpler though - I no longer get the option of specifying a COM port for either the Pico or Pico 2, in either 4.2.0 or 4.4.0.

This happens while the COM port is listed in Device Manager, and works fine if I use TeraTerm to connect to it - I just can't get the IDE to connect to it because it won't give me the option. I can put either the Pico or Pico2 into .uf2 boot mode and it the Tools menu then shows an entry for:

Port: "UF2 Board"

so I can upload to it, but the COM port remains hidden in the IDE.

I've tried resetting the driver for the COM port with Zadig 2.9 and by using a .inf file:
pico and pico 2 serial infs.zip
These are for Windows 7 and 8. I don't know if they'd work on later versions.

Either way, the behaviour remains the same - the COM port shows in the Device Manager and works fine in TeraTerm but isn't listed by the Arduino IDE so it can't be used to upload to and the IDE's own serial monitor can't be used.

The relevant discussions for the RP2350/Pico 2 upload / COM port problems were #2645 and #2656

[Andy2No]

Okay, it seems this is a known problem with upgrading STM32 boards support for Arduino IDE 1.8.19 - completely unrelated to this core but it causes the problem with Port if the STM32 boards support is upgraded beyond 2.7.1, which I did sometime within the last few weeks. See:

https://forum.arduino.cc/t/arduino-ide-1-8-19-in-tools-menu-port-grayed-out/1287639

There is a suggested workaround there which I haven't got my head around yet, but uninstalling STM32 boards support 2.8.1 from the Boards manager, then installing 2.7.1 instead fixes it, though it seems only after exiting the Arduino IDE and starting it up again.

It seems the cause is adding a list of VID/PID pairs for different boards, one of which is broken or not compatible. Somehow that breaks the Port menu for the whole IDE.