Hi - to set the table for this problem, my instance of X-Plane 11 used to work. I was flying a Cherokee 140. Flying around KMLB. Running a MacBook Air (I know this is a stretch processing power wise, but it did work). Seemingly out of the blue, upon launch of X-Plane 11 I started receiving the following message "Loading navigational data failed: Absolutely no navdata installed" and would get bounced out of the program. The only thing that I changed, is that I upgrade my Mac OS to Mojave 10.14, I have not touched anything else within the X-Plane directory structure. Are there any X-Plane 11 problems associated with upgrading the OS on the Mac? Any ideas on what I could do to restore the navdata it obviously thinks is missing. Or Uninstall/Reinstall instructions?