The boot loader on the nano 33 BLE changes the port used when uploading but the Arduino IDE is not coping with the change correctly. On my system the Arduino uses port 8, with port 8 selected in the tools menu when an upload is performed the port changes to port 6 and the upload continues as normal, at the end of a successful upload the port changes back to 8 but does not get selected in the tools menu(this means that if you don’t manually select the port again the next upload will fail) , surly port 8 should automatically be selected in the tools menu as then no-one would even know or care about the changing com ports.
I am using the installed version of Arduino IDE 1.8.12 on windows 10
I was directed to post here from the forum.

Thanks.