VooDoo is apparently having some very strange FG issues - I wonder if we might have a crack at solving them this evening, if he is able to be about? I have a couple of ideas about what might be causing scenery issues (it seems FG got fussier about where it reads scenery from - I had this experience myself, but managed to work around it quickly and cleanly).
I had my share of scenery problems and therefore I have some experience. But I am on Linux, so maybe there are differences to Windows.
Anyway, I tried many combinations of download possibilities and for me the ONLY thing that worked (and still works since ca. 9 months) is the combination of the latest terramaster for downloading before flying and at the same time having terrasync enabled for refreshing out of date scenery. This works quite well since for the time that terrasync updates, you still have the old downloaded scenery for flying anyway. Maybe not as pretty but usable.
Oh and another experience: Before starting above system I had to delete ALL scenery folder content. ALL! And then start completely from scratch. It took some time before I understood that even above combination gets confused if there is any old scenery data anywhere around.
I am convinced 90% of FlightGear crash issues are scenery-related. Sometimes there are core system bugs, which to be fair usually get ironed out these days. Sometimes there are MP aircraft issues - and in this case, those aircraft need to be identified, and their custodians should be held to account to fix them quickly.
I think FG has, in general, become more picky about where it imports and exports files to and from, and in doing so, I think the potential for scenery issues has increased. I concur with Hans' findings - a complete ground-up approach to scenery is required.
With VooDoo's problem, the first approach I would suggest is using FGRun to completely limit where the program looks for scenery, and then working through the various directories one by one - Terramaster dloads, his manual Terrasync download, the auto Terrasync dload, the My Documents and the Roaming folder... there are all sorts of places old/incompatible files could be hiding. It's quite likely this has already been tried, but if not, that's where I'd start.
I've started a new thread in a more logical location for discussion of FG stability issues in the current versions - this thread is still a valid place for immediate, temporary problem solving attempts, but for a longer term approach, please consider posting in the
Crashed and Burned thread