Second monitor on HDMI quit working when laptop closed

I’m having a random problem with my UD-ULTC4K. For no reason I can identify, I can now only get my second monitor, connected via HDMI, to work when my docked laptop is open, rather than closed. If it’s open, the laptop monitor, my DP monitor and my HDMI monitor all work and can all be extended. However, when I close the laptop lid, the second monitor goes dark, regardless of my Windows Display setting. This just started happening with no change in FW, software, hardware, cables, etc., so I can’t figure out what caused it.

Any hypothesis?

Hi Jeff,

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

I recommend trying to force the external displays into extended desktop mode to see if this helps:

  1. Connect the docking station to the computer with both displays connected
  2. Close the laptop lid
  3. Use the Windows keyboard shortcut: [Win]+[P] ( Press and hold the Windows key, then tap the ‘p’ key, and release both keys )
  4. Select the top option to enable only one display
  5. Repeat steps #3 & #4, but select the “Extend” option instead

Please let me know if this helps to restore the two external displays with the laptop lid closed.

If the display is still not working, our next step is to get some additional information from your system using our log-gathering tool: PlugDebug, when you have a moment:

  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 ( )
    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 ‘’ with the subject line ‘Ticket #405384 - Attention Pat’

This will allow us to examine some log files from your system to check for any rolled back drivers, out of date drivers provided through Windows Update or the system manufacturer, or any potential configuration issues. 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 and we’ll be happy to help.


Plugable Technologies