I have wondered about this button for some time now.  After browsing thru some of the forum threads, I just decided to satisfy my curiosity with this thread.  When the Lorby Scenery Export first came out, and you had to run it yourselve, I thought it was a nightmare.  Then, Pete Dawson came to my rescue and came up with a way to include it into just dropping an .exe  file along side the makerwys.exe file and a LorbyScenery.cfg file appeared.  Running the MakeRwys.exe file now takes awhile since I have installed a number of the Orbix files (no individual airport addons), but I thought the Rebuild Scenery DB Button had been now passed up.  Do I still want to run this button?  If I do, it seems to just sit there, and I finally click on OK and it moves on to the next one.  Whats the low down on this Button?

Mike Nicholson, Jetline Systems PC, 4.20 Intel 4 Core i7-7700k CDU, Nividia GTX 1060 6GB card,  32722 mbs memory, Windows 10- 64bit, Prepar3D v4.5 Pro

FSUIPC5 and MakeRwys 5.11.

If you look in the RC data folder you'll find a number of csv files. Those contain all theVOR, NDB and waypoint info required for your flight plus airport info. Unless you keep those files up to date you will hit problems. Every time you add scenery run the database update which in turn calls makerwys.exe.

All explained in the manual bar the bit about Lorby's excellent program which is called behind the scenes for the aiports installed as add-ons.