Screen Flickers on HDMI when VGA running as well

I am using a UD-3900 USB 3.0 with two video outputs a projector (Promethean PRM-30)connected to the HDMI and another projector (EPSON H328A) connected to the VGA output. I am running Windows 10 from a Toshiba Sattelite C 55D-B. Without the VGA connected I have no problems. When I connect the VGA, the HDMI output flickers. The amount of flickering varies and occasionally is absent. What could be causing this?

Hi Stein, thanks for posting! Sorry to hear of the behavior you are seeing intermittently, it is certainly strange, and I will be happy to help!

Based off of your description, we’ll want to reinstall the DisplayLink drivers and run the DisplayLink cleaner tool to make sure the software is in a good state. To do so, please follow these steps:

  1. Disconnect the dock from the system and please remove the power cable from the dock so it turns off completely. Please keep it disconnected until the last step
  2. Uninstall the DisplayLink Core software from the Control Panel -> Programs and Features. Don’t worry if this fails, just move onto the next step
  3. Download, extract and run the DisplayLink cleaner tool, found here –>… and ensure it displays “Cleaning Complete” when done (video walk-through ->
  4. Once the Cleaner has been run, reboot (even if not prompted to)
  5. Now download and install the 8.0 M2 DisplayLink software, found here –>…
  6. Reattach the power cable to the dock first. Once the dock is powered on, reconnect it to your system when prompted by the installer which will trigger the final portion of the installation

If these steps help, great! If not, we’ll want to examine some log files to see if they can tell us what is happening. To help us do so please download and run our diagnostic utility PlugDebug –> just after the behavior has occurred and you have restarted so we can try and capture the behavior. Please send us the file that is created on your Desktop by sending it to our direct support email address at with ‘Ticket Number 153717’ in the subject line so we can match everything up. We’ll examine the logs and determine next steps from there.

Thank you,

David W.
Plugable Technologies