Plugable USB 2.0 UGA Multi-Display Adapter was working on mac not working on mac mini

hi, I have been using the Plugable adaptors for 2 add’l (Dell) monitors on my imac (2011) and they worked great. I just switched to a (late 2014) mac mini (OSX 10.10.5) and ordered a 3rd adaptor so I could still have 3 monitors. Everything worked fine for a couple of days, then I started getting some degradation on one of the monitors. I unplugged two of them to switch the adaptors and try to isolate the problem, and every since then I cannot get any monitor to work on the USB port with my Plugable adaptors at all. (Note, this was a ‘hot’ unplug, I did not power down monitors.)

Very frustrating since everything was working fine initially! Other notes:

  • USB ports still work for other devices
  • I now have 2 monitors plugged into the two thunderbolt ports, but initially had one in thunderbolt and two others with plugable adaptors through USB – that was working until i briefly unplugged the cords.
  • I have also tried plugging the 3rd monitor into the hdmi port but the mini only officially supports two monitors so it only works if i unplug one of the thunderbolt monitors. From what I glean of other people running 2+ monitors on a mini, it seems the 3rd monitor must go through the USB port.
  • most mystifying, the exact same dell monitors with the plugable adaptors work fine when we move them to my wife’s 2010 MacBook Pro running OSX 10.10.3.
  • have tried PRAM reset and plugging in monitors in different orders, nothing changes

so is it an issue between the new Mac Mini graphics card and the plugable adaptor specifically? help! I am at my wits end, once you go to 3 monitors it is impossible to operate with two! Thanks for any help!

Hello Tricia,

I am very sorry to hear this! I would fist try a clean DisplayLink driver installation:

  1. Disconnect display adapter
  2. Uninstall the current DisplayLink instance in your “Applications” lineup
  3. Reboot
  4. Install the latest DisplayLink driver from… (just hit Agree)
  5. Reboot
  6. Attach display adapter and test

If you end up with the same issue I would need to take a closer look via PlugDebug. It allows us to get a better idea of which driver versions are on the system, as well as diagnostic and installation logs, while minimizing the amount of questions we send your way when we are looking into an issue.

Please head over to -> There you will find a download link as well as instructions. Please be sure to have the display adapter plugged into the Mac with its monitor attached when running this tool and attach the resulting zip file in a direct reply to (this forum platform won’t let you attach .zip files). Once we have the .zip file it generates, we will get a better idea of how to best proceed.

Kind regards,
Plugable Technologies

WOW! SHOCK & AWE! I could not be more impressed with Plugable at this moment. Re-installing the driver worked. All 3 monitors up & running. I wish I would have checked in here before I killed myself trying every other solution I could think of! Also most impressive how you were willing to take the next debugging step if the fresh driver install had not worked.

Question: Can you intuit what happened? Did the driver somehow get messed up and that’s why the display initially started to degrade? Or was it when I hot-unplugged the displays? If the latter, will the degradation return, do you think?

Thank you! Thank you!

Hello Tricia,

You are welcome. Glad you are back up and running. It is hard to say exactly what happened without the logs. What I can say is that reinstalling the DisplayLink kernel module forces it to re-flash or flash the display adapter with the supplied firmware thus forcing functionality.

You can contact us anytime (also directly -> if you have any further questions.

Kind regards,
Plugable Technologies