I have two Arduino UNOs. When I connect one (Board1) to the PC via USB, it doesn't Windows Device Manager doesn't display Arduino on COM 4 it just says
USB Serial Device (COM4),
but Arduino shows it's using COM4 . I can upload a sketch to that board and it runs. The Port menu in Tools shows COM4 (Arduino Uno)
With the other board (Board 2), which was running previously using COM10, when I upload the sketch, it immediately comes up with
java.io.IOException: jssc.SerialPortException: Port name - COM4; Method name - setEventsMask(); Exception type - Can't set mask.
Caused by: jssc.SerialPortException: Port name - COM4; Method name - setEventsMask(); Exception type - Can't set mask.
... 4 more
The Port menu in Tools says COM4 - no mention of Arduino Uno.
I have re-installed Arduino twice. This all began happening after I had left Board 2 connected to USB for several days. I have rebooted the PC (Windows 10) several times and reset the boards.
Any help would be gratefully appreciated.