Connecting usb to arduino resets OS X

I have Macbook pro with latest Sierra OS X. Arduino IDE is installed and is 1.6.8

Every time I connect Wemos D1 board with USB cable to Mac it resets and will not boot up if usb is connected. this was not the case in the summer (probably previous version of OS X) and I was able to program these boards.

Anyone seen this and how to fix? Or do I need to get old PC laptop with linux to be able to program my boards? Any help would be nice :)

See https://forum.arduino.cc/index.php?topic=428349.0