Ok i just tried the same thing. Starting with a blank scene i created one standard procedural terrain, then went in the editor and clicked zero edges and dug a big trench in the terrain. I could then enter and exit the terrain editor and it did NOT change the terrain each time at all. So it seems that possibly there is a bug with your version Vue as i could not reproduce the problem. I can say definitely you should not be having the terrain change each time you enter the editor if you have not made any deliberate changes. I can only suggest getting the latest update, i use Vue 5 Esprit and it is relatively stable and free of this bug. If you have Vue 5 Infinite maybe you should ask at E-on about this bug because it may have not been picked up yet? This would be an annoying problem and i can understand your frustration. Sorry i can't help you any more than to say that it shouldn't happen! -Jeff