How I got Luna to work as a "third display" (mac mini)


I initially couldn’t get Luna to work on a system where I already had 2 display’s going. Here is how I solved it.

Summary: Monitor 1: Thunderbolt/USB-C, Monitor 2: HDMI, Luna - Thunderbolt/USB-C


  • I have a 2018 Mac Mini that comes with 4 Thunderbolt ports in a USB-C connection. Prior to getting the Luna Display, I was running two 23-inch monitors, both via Thunderbolt/USB-C
  • I tried to add the Luna dongle into the 3rd Thunderbolt/USB-C connection and luna wouldn’t start
  • I did some online research suggesting the Mac Mini is capped at 3 displays - and to achieve this, HDMI must be used for one of the monitors. One (apparently) can’t just keep using the available Thunderbolt/USB-C ports
  • I switched one of my 2 full size monitors to use HDMI, and used Thunderbolt/USB-C connections for Luna and Monitor 2

Everything worked!

I’m still exploring Luna - but I didn’t find info in the community about this issue and wanted to post a solution that worked for me. From my perspective, this is a Mac issue and not a Luna one

(extra credit: I found youtube videos where users had connected 6 monitors to a mac, but were using external graphic boxes to do so)


I got the third display working on my MacBook Pro after just a few minutes of fiddling around. I believe this is when Luna support said they didn’t, well, support it. It’s pretty cool to have, though.


Very cool - can you describe your set up? (what monitor is plugged into which port, type of connection, etc.)