External Monitor Doesn't Show in Display Settings (Mac Os 10.13.1)


I have a monitor connected to the Plugable UD-3900 using an HDMI cable. The monitor doesn’t show up in display preferences. I’m running Mac OS 10.13.1 and I have installed DisplayLink Mac Driver Version 4.0.


Hi Susan,

Thanks for contacting us! I’m sorry your new docking station is not working as expected and I would be happy to help.

One quick question for you…can you confirm you are using a standard HDMI cable (one with a HDMI connector on both ends) to connect your monitor to the dock’s HDMI output? I ask because other types of adapters or cables can cause problems (for example any cable with a DisplayPort connector will not work).

Assuming for the moment a standard HDMI cable is in use, one quick thing to double-check is that the source video input of the monitor is set to HDMI. This is important because monitors with multiple inputs may not switch to the preferred one automatically.

If the source video input checks out, our next step is to perform a fresh install of the DisplayLink driver to ensure it is in a good state. If you would, please follow these steps:

  1. Disconnect the dock from your Mac and remove its power cable so it resets. Please keep it disconnected until prompted.
  2. Follow the steps here -> https://plugable.com/drivers/displayl… to uninstall the current driver.
  3. Reboot the system, even if not prompted
  4. Download of fresh copy of and install the latest DisplayLink driver for Mac from here -> http://www.displaylink.com/downloads/… (we have a detailed walk through if you need it here -> https://plugable.com/drivers/displayl…)
  5. Due to security changes made by Apple in High Sierra, you may be prompted by a ‘System Extension Blocked’ warning during the installation. Should that occur, please follow the steps here -> http://support.displaylink.com/knowle…
  6. Once complete, please reconnect the power to the dock, and then reconnect it to your system.

Please let us know if that helps!

Plugable Technologies


I have the same issue with MacOs High Sierra 10.13.1 but I hace 5 VGA monitors plug to my MacBook Air 1.7 Ghz Intel Core i7, 8GB 1600Mhz DDR3, Intel HD Graphics 5000 1536 MB.

My recognize the screen but all of them are black. !](https://d2r1vs3d9006ap.cloudfront.net/s3_images/1675494/Plugable4VGA1tunderbirdVGA_inline.jpeg?1511458705)](https://d2r1vs3d9006ap.cloudfront.net/s3_images/1675494/Plugable4VGA1tunderbirdVGA.jpeg?1511458705) !](https://d2r1vs3d9006ap.cloudfront.net/s3_images/1675495/5VGAmonitors_inline.jpeg?1511458723)](https://d2r1vs3d9006ap.cloudfront.net/s3_images/1675495/5VGAmonitors.jpeg?1511458723) !](https://d2r1vs3d9006ap.cloudfront.net/s3_images/1675496/5VGAMonitorsRecognized_inline.jpeg?1511458739)](https://d2r1vs3d9006ap.cloudfront.net/s3_images/1675496/5VGAMonitorsRecognized.jpeg?1511458739)


Hi Alexander,

Thanks for posting, appreciate the photos. If you follow the steps I mentioned above, does that help get things going again?

Thank you!



Yes, it did.

But I one more question, How many monitors is the max I can add by using plugable (USB/VGA)?

I currently have 4 working properly but the 5th is not working.

Please advise.




Hi Alex,

Thanks for getting back with the update, and I am glad to hear that the adapters are again working as expected.

To your follow-up question…the maximum number of DisplayLink-based USB video adapters (all of our USB video devices are powered by DisplayLink) that can be connected to a Mac system is four, so the behavior you describe is expected.

Thank you,