Q: Why my MBP always "runs in to problems and needs to restart" after I disconnect my audio interface?

When I try to disconnect my Steinberg UR44 Audio Interface from my MBP, the computer always blacks out and says it has run into a problem and needs to restart. I always double check if the program that uses the interface is closed. It happens either when I try to unplug the USB cable no matter if the interface is on or off, or when I turn off the interface while USB cable connected. I just updated to OSX 10.12 and the thing happens every time since the update. As far as I can remember, this situation never took place before.

I really appreciate if anyone could help me out.