Thanks for contacting Plugable! I’ll be glad to assist.
We’ll want to proceed with a clean installation of the DisplayLink drivers, just in case the previous uninstallation left some items behind. We’ll do all of the following with the dock power and USB disconnected, until the very last step.
-Disconnect the dock from the computer
-Uninstall DisplayLink Core software from Control Panel->Programs
I have the exact same setup and issue as the original poster: Surface Pro 3 with UD-3900. I have 2 external monitors: one HDMI, one DVI. Has been working fine for many months. After installing the latest Plugable drivers, the external monitors are seen by Windows and recognized but the displays are dark. I followed the recommended corrective steps but the issue remains.