I'm not sure what's happened when I made those duplicate FS9 installations, one for the 1950s, one for the 1960s, and also Golden Wings for everything up to 1950. I transferred all the necessary folders from the original FS9 into the dupes, so you would have thought the common F-86 files would have transferred along with them. Looks like they didn't. I've had a lot of weird things happen with FS9 on this machine. Example - I can install an unlimited number of textures plus add-on sceneries. However, I haven't installed any effects from downloads at all (though I've saved them in their own folder), and am using the default FS9 effects, because that's what caused the sim to crash the last time - there was some kind of problem with it reading the effects from the Flying Stations Canberras, and that locked the sim up. I saw an app some time ago that purports to clean the sim's registry files. Is there any validity to that claim, and is it worth cleaning just the sim's registry files?