Issue with tbt3-udv and second thunderbolt 3 port driving a monitor

We just picked up a tbt3-udv dock and we are having problems getting it to recognize a monitor plugged into the second thunderbolt port. We have a usb-c to DP cable that doesn’t work from the dock, but works properly connected to the second thunderbolt port on our MacBook Pro’s. We also tried the apple usb-c multiport adapter using an HDMI cable and get the same result.

I have tried to update to the latest display link drivers to see if that would resolve the issue, but id doesn’t. While we have a work around we would rather be able to keep the extra port on our computer clear for additional devices as needed.

Any ideas on how to solve this issue?

Hi Ron,

Thanks for posting! I am sorry your new docking station is not working as expected and I would be happy to help.

Thank you as well for the detail you provided and the troubleshooting you have already performed that is much appreciated. A quick note, the DisplayLink driver you mention is intended for our USB docks that feature DisplayLink technology, and is not required when using our Thunderbolt 3 dock. Please uninstall the driver at your leisure by following these steps ->…

To the issue at hand and based on your description of the behavior, a few quick questions for you…

  1. Can you confirm that you are using only the Thunderbolt 3 cable that was included in the box with the dock to connect it to your MacBook Pro (MBP)? I ask because other cables can potentially cause problems.

  2. Do you also have a display connected to the dock’s built-in DisplayPort output (or using the included DP-HDMI adapter), and it is working properly?

  3. If the answer to #2 is yes, if you temporarily disconnect the DisplayPort connected display does the display connected to the dock’s second Thunderbolt 3 port using the USB-C to DP cable start working properly?

Thank you in advance for your patience, and giving us the chance to help!

Plugable Technologies


You fixed it!!

  1. Yes we are using the included Thunderbolt 3 cable.

  2. Yes, the DP-HDMI adapter was being used and working properly.

  3. Yes, disconnecting the DP-HDMI adapter allowed the other monitor to work. Upon plugging that back in both monitors worked correctly.

Thank you

Hi Ron,

Thanks for getting back with the update, and you are of course most welcome for the help. I am glad to hear that everything is now working as expected.

Should anything change in the future please keep the dock connected to the system with both monitors attached, even though one is not working, and please send a System Report (instructions below) to with ‘For Ticket # 217892’ in the subject line so we can match things up and determine the next steps.

If you could also include the Amazon Order ID number for the dock purchase (available from in your email that will be most helpful.

Thank you for your patience, and please have a good weekend!


System Report Instructions:

  1. Choose the Apple Menu -> About This Mac.
  2. From the window that appears, click on the ‘System Report’ button.
  3. A System Information window will appear. From the application menu bar, click on File -> Save… to save the information to a file.
  4. Attach the saved file to your email response.