RELEASE 2.4.2 BUG perhaps ... is anyone aware of this ? When uploading a sketch using arduino IDE 1.8.5 with arduino board 1.6.20 .. sketch upload takes a while to build/rebuild and then suddenly jumps to filaure ..COM PORT X not found ! ..there is little if any time window for a flash button press. I reverted to 2.4.1 and problem is now gone after spending hours figuring out why
Yes, as I said, there are things in our core that tend to trigger the IDE problem. I'm not aware of the details of why the IDE decides to go off the deep end so often, so I can't explain further. Just go download a newer IDE (hourly or beta) and try it out.
I don't know about the portable, I've never used it