Everything was good in FSX until a recent update from Orbx went south, the sea was replaced with sand and airport elevations were destroyed.
Although comical I was not impressed with the way Fsx looked. I was not looking forward to a re-install of FSX and every addon.
Spent a few days looking on the Orbx forums on how to fix my problems, Two files were mentioned the Terrain.cfg in the main FSX folder and the lclookup.bgl found here C:\Program Files (x86)\Microsoft Games\Microsoft Flight Simulator X\Scenery\BASE\Scenery
I was lucky as I had installed Orbx at the same time on another pc so I just copied these two files over to this pc. I now have water where it should be and my runways are not buried in the ground.
I had a quick flight and it looked slightly different as it has altered the FSX cfg as well, a bit of tinkering should put that right. I also had to replace the scenery.cfg with my backup as that was also corrupted.
Replacing these two files saved me from a re-install headache for which I'm very grateful.
If you use Orbx and it's working ok I would back up these files to be on the safe side.
Terrain.cfg --- found in the main FSX folder
lclookup.bgl --- found in the Microsoft Flight Simulator X/Scenery/BASE/Scenery folder
scenery.cfg --- C:\ProgramData\Microsoft\FSX (hidden by default)
FSX.cfg --- C:\Users\PC Name\AppData\Roaming\Microsoft\FSX also hidden by default.
Hope this might save you some grief in the future.