Hi Rehabman, My situation: Laptop connect on dock. External screen attached on dock by DP port. MacOS version is 10.12.6 Problem: With the laptop lid closed. 1)System's automatic sleep always turn to shut down. if I use Apple->Sleep, it works very well. 2)System can't turn on. it boots loop. While with the laptop lid open, system turn on without any problem. The problem that listed above didn't appear when I use Yosemite. Thanks for your effort to add dock support.