Given the supposed "disaster" of bugs that I was expecting since the xbox launch had gone so poorly, I've been surprised at how few bugs i've encountered. I have about another 15 or so esp mods I've been running alongside it, yet I haven't encountered a single conflict with any of them. Maybe I just got lucky, but I'm gald they delayed the release for PC as i can see how some of the bugs that were mentioned could be completely game-breaking. No offense, but you mainly have yourself to blame for that. Save corruptions, while very unlikely in the situation you're describing, have always been an issue for TES/Fallout games. Thus, you should ALWAYS backup your saves before you do anything that introduces something new into the game, whether it's a new mod, a DLC plugin or even after removing mods. While the gamesave files tend to get very bloated, you can easily compress them down into a rar archive or something, as you will likely cut down over half the size of your collection of saves just by doing that. Now, that being said I find it hard to believe that loading the dawngaurd plugin simply "broke" you're save. What's more likely to be causing the issues would be any mods you've installed that conflict with the data in your dawnguard plugin. If you have any mods installed, I'd suggest you turn off anything that modifies your characters behavior, or anything that had made changes in an area that is now used during the dawnguard quest. Most graphics mods like texture replacements or FXAA injectors should be fine, just be weary of any plugins that might be similar to the DLC itself.