stevstrong

I don't know how WIn11 manages the ports but from your post I think that Arduino access to the port is prohibited. Have you installed the serial driver with admin...

Can you please check if [338020b](https://github.com/rogerclarkmelbourne/Arduino_STM32/commit/338020bee1491a3876d4b0bdd26ea0a395c89c38) solves the issue?