[TOPIC MOVED]How do i delete all the addon sceneries and return them back to default ?

[fruitfly]

Sure; install another FS9! Serously!
That way you can still use your old one and update the new installation with addons like Ryanamur had explained. Once you are finished
and everything works, you can uninstall the old FS9.
I was just about to explain how when I found something PRECISELY for this situation. (if you decide to do that):

http://www.flightsim.com/cgi/kds?$=m...ultfs9.htm