The cause of all the problems, i.e. CTD when attempting to start a flight from KJAC or flying into KJAC (see previous posting), was a .bgl located in Scenery World Scenery "grand_teton_VTPH.BGL". Removal of this has restored the area back to normal. Now have to find where the .bgl originated. Thanks Mel for your time and help. Grant (Echofox)