Alright so this is apparently a problem a few people have been having, but I have yet to find anywhere with an actual solution. I apologize if this has already been answered and I'm just missing it, but still... So, basically, I've just been turned into a vampire, gone through the tutorial and everything works out fine. Okay that's great. Now I'm told to go and talk to a vampire by the name of Garan Marethi to start the first quest. So I go over to him and talk to him, or try to, and he just says "Mortals aren't allowed in these halls, not even you" and then tells me to find Lord Harkon to 'correct' the problem. However, I'm already a vampire I've tried multiple reloads, redoing the dawnguard quest from a new file with no mods or custom races, and a reinstal of the entire game. Nothing's worked, and this is getting gradually more frustrating. Thanks for any helpful tips or anything.
