Hi MarkM
Just me try and make things less frustrating. It sounds like the DisplayLink chip in this dock (DL-3900), which provides the audio Ethernet and video on this dock, is not being recognised on the USB bus.
V5.6 will not work with this dock, as v6.0 was the first release to support our DL-3xxx family. So let'ss try getting it working with v6.3 release.
As it sounds like the chip is not being detected on the bus, but you don't say if you are connecting to USB 2.0 or 3.0 ports. My first though is "Are you connecting it to a USB 3.0 port?". We know that early versions of host controller drivers have bugs that prevent it correctly recognising our USB 3.0 devices, which they have fixed in later releases.
Check out
this article on our website to find the latest USB 3.0 drivers
If this is not the case, please can you post the system logs, with the dock connected, and 6.3 installed to see if that gives any further clues to the issue?
http://kb.displaylink.com/269
Thanks
Wim