I reported this in another thread but it's clearly a unique issue, so moving here. (from here: https://forum.arduino.cc/index.php?topic=658768.msg4441475#msg4441475)
I don't see an error, just hanging when trying to upload. It just says "Busy" and progress bar rolls forever.
Here is my log output: https://gist.github.com/jywarren/50235371477b10d4e9815c4babef6e9d
I also briefly saw an error message that the compiler wasn't working. But the log seems to indicate that step was OK. And that error message didn't recur.
About 30m before this first began last night, I was able to upload, and then it stopped working. I'm on a Chromebook, with Arduino Micro - is there still an outage or a bug going on?
I suspect it may relate to this command in the log, which seems to have
undefined where there should be a filename?
Programming with: avrgirl-arduino flash -f undefined -a micro -p /dev/ttyACM0