[Harnage]

Maybe if you uninstall the game and then manualy delete the IL-2 Sturmovik 1946 folder(storing a backup of your missions folder or PaintSchemes or whatever)
And then reinstalling everything.

I recently had to reinstall myself and I notice my IL-2 Sturmovik 1946 folder had everything still in it after uninstalling the game.

Hope this helps.