Hi,
Can you let me know what the error code is of the device that is showing the yellow exclamation mark in device manager?
As soon as the issue is seen please attach the output of this tool:
http://www.displaylink.com/support/ticket.php?id=269
Once downloaded, please run it and select "Gather Support Information"
It's also worth trying the "System Compatibility Check" to see if anything is flagged up.
Thanks,
James