Important Must Have File
Most users of FSX are aware that it is not a perfect product despite the hard work of those dedicated people who worked for Aces Studios who created it.
Way back in November 2006 two guys, Richard Ludowise (rhumbaflappy) and Luis Feliz-Tirado took a look at one particular file, the terrain.cfg file and found that they could correct some of the faults in FSX by adjusting this file's contents. The file is a 'simple' text file.
They used as an example the fact that the River Thames both in default and with Photo scenery active had rocks showing in the middle of the river at various places. By correcting errors in the the code they were able to stop the river climbing out of its bed and remove the rocks. Errors throughout the FSX World were corrected.
Other corrections made the file much more powerful and highly useful to developers of scenery.
If you don't have this updated file installed then you should get it straight away. It is available from: -
http://library.avsim.net/index.php Search for: fsx_modified_terrain_cfg.zip
The package contains install instructions which are very simple to follow.