Fortunately I'm just starting to play around with Luminar 3, and Luminar in general, and since L3 installs side-by-side with L2018 anything I did in L3 didn't affect my L2018 install. With that in mind I ended up deleting the "Luminar Catalog" in my Pictures folder (the default install location on Win machines) and that took care of it. During a Facebook presentation tonight a Skylum rep mentioned that for "performance reasons" it is best to add images in small batches to the Library so I'm guessing that me accidentally trying to add a 50gb folder was a bit too much for it.
On a bit of a downer both of my questions during the live chat were seemingly ignored. I wanted to know if their road map plans included being able to view the full meta tags, similar to Adobe Bridge. No answer but they did answer somebody asking if the ability to edit EXIF tags like Copyright & similar will be coming. Yes to that question. I also wanted to know if the feature set was the same between the Mac & Win versions. No answer to that one and I'm not sure if I've seen that particular question addressed anywhere.