Apr 2, 2018 - After updating to macOS 10.14, the DisplayLink 5.0 drivers will need to be. To address the video issue that arose for Mac users who have installed the. Technology, such as USB docking stations and video adapters. Can be found on DisplayLink's website at: http://www.displaylink.com/downloads/macos.
After getting frustrated with this adapter last night because it was not working despite following the instructions, I decided to try reinstalling the driver today. My hunch was that the driver did not install correctly last night because of an issue with the instructions. Specifically, the install guide states that after the install completes you need to go into the Security and Privacy setting and click 'Open All' to essentially accept the code's digital signature and allow it to run. My guess was that by accepting this signature after the installer tried to update the pre-boot settings did not allow the driver to properly install. That would also explain why the device did not appear to do anything last night when I tried it.
The screen would just remain blank and never received a signal. However, after reinstalling the driver, the device is working great! Scrolling, text entry, and videos are smooth. Honestly, I can't tell a different from a regular HDMI output. Your mileage may vary though depending on the processor. I'm running a Core i7 from Mid-2014 with 16GB of RAM, so that may help.
Overall, if you run into an issue with the install where you're just getting a blank screen on a Mac, try installing the driver again after you accept the digital signature (by clicking 'Allow') in the Settings - Security & Privacy menu. It worked for me, and will most likely work for you too! Definitely a much cheaper option than buying a new Mac too!