Hi :), I'm using an arduino micro on a pc with win 10, everything works fine until yesterday. Today I can upload the code and it works fine, when I open the serial monitor it should display some data, but the serial monitor is totaly empty. Sometimes after uploading the code, when I try to open the serial monitor, an error message pops out "Board at COM4 is not available". Someone has this problem too?
At the bottom right corner of the serial monitor there is a menu of different baud rates. Check if the value selected matches the number in the Serial.begin() line of your sketch.