I'm encountering another type of bug, not exactly mentioned here. It's a travel bug: whenever I fast travel or simply enter a cave or a structure, after the loading screen I can hear the indoor music and enviroment sounds (like running water), but the game freezes and I only see black screen. I've tried waiting, but it didn't help. This started happening only when I started playing Dawnguard. I'll try to experiment with mods (I have 60+ active mods) and test it all out. I'll reload an older save, turn off all mods and play with pure Skyrim and Dawnguard, and add mods, one by one, after sufficient testing. If anyone else has a travel bug, and has experimented with it, please share your knowledge.