UD-ULTC4K Third Monitor Not Detected on Dell XPS 17 9720


I am having a strange problem where if my Dell XPS 17 9720 is connected to the docking station and powers up, it intermittently will not detect the third monitor. I am able to get around this by unplugging the dock from the laptop, unplugging the dock from the power source, plugging the dock back into the power source after 15 seconds, and then plugging the dock back to the laptop. Once these steps are completed, the third monitor is then detected.

I believe I have all the correct drivers on the laptop as once the third monitor is detected, it works flawlessly. However, there is no pattern I can find where this problem can be replicated. It seems to happen inconsistently and in various scenarios (i.e. from bootup, to waking from sleep/hibernation, connecting/disconnecting from power source, etc…).

Any guidance would be much appreciated.



Thanks for contacting us! I am sorry this is not working as expected.

Based on your description of the behavior, our first step is to get some additional information from your system using our log-gathering tool: PlugDebug, when the display next fails to detect please perform the following to gather a log file from the computer.

  1. Keep the docking station connected to the computer with the displays and devices connected to the docking station
  2. Download and run our PlugDebug utility ( http://plugable.com/support/plugdebug )
    2a) Choose the Download link for your operating system and save the PlugDebug executable to your Downloads or Desktop
    2b) For Windows: Right-click on the PlugDebug application and run as administrator
    2c ) For macOS: Select the PlugDebug utility from the Downloads pop-up on the Dock, or double-click if saved to the Desktop
    2d) Follow the on screen instructions to launch the application
  3. Click the “Start” button to begin gathering logs from the system
  4. When completed the application will pop-up a message with the name of the zip file containing the logs on the user desktop directory
  5. Please attach this zip file to your reply email to ‘support@plugable.com’ with the subject line ‘Ticket #405598 - Attention Pat’

This will allow us to examine some log files from your system to check for any out of date graphics drivers that may be causing intermittent display detection ( but not affecting detected display performance ) as well as to check for any power settings or configurations that may be affecting the docking station’s connectivity, and to help determine the next steps.

Thank you,

Plugable Technology


We’re closing this thread due to inactivity, but if you have any further questions please feel free to contact support@plugable.com and we’ll be happy to help.


Plugable Technologies