Hello Masters, i am fighting with this issue for days, I read an try to revive my Cactus Micro R2 in double clicking the reset button but nothing appends (i am on OS X 10.11.5) with IDE 1.6.8. Please if someone can help . in fact my data cable was pulled out before the program was totally uploaded on the Cactus 
Please run the command line in Terminal.app when usb plugged
ls /dev/tty*