I couldn't see an official bug list for Dawnguard, so I thought I'd make one myself for people to add to so Bethesda have a good list of what needs fixing, and I'm sticking it in the spoilers section so people can feel free to give as much info as possible without ruining the game for others. Please keep it concise and to the point, no whinging and hurling abuse because bug a or glitch z has really annoyed you.

The game has been crashing on occasion for the first time since I started playing in borderless windowed mode.

The sound keeps cutting out, random words in sentences will not be spoken.

Serena keeps her vampiric look after being made human, can still use vampiric abilities and, according to the wiki, can infect the player with vampirism during combat.

Sarana cannot be asked to perform actions like all other followers can.

Serana's armour is bugged so she will not equip any armour that is not hooded armour (such as the Hooded Thalmor Robes), this cannot be fixed with console commands, either.

Serana seems to be unable to equip a full set of armour, she will randomly decide not to wear a certain pair of gloves, boots, or hood regardless of what I try.

The guy in Dawnstar who will take you to Castle Volkihar does not take you there after you finish talking to him and get into the boat.

I cannot buy the Alchemy lab for my home in Whiterun, if I try to do so, I will lose 500 gold but I will not get the lab.

Serana will start sneaking for no reason, just doing the silent roll forward to catch up to you, and will not stop unless you force her to take another action (sheathing weapons sometimes works, entering battle, or just Shouting at her, which I had to do after she got herself stuck and would not move).

Last night, I got a glitch where she kept getting really high up in the air, or going below the ground both in and out of combat, was fixed by restarting Skyrim, but it did mess up the final boss fight and dialogue scenes with the final boss right before you fight him directly.

On the Xbox 360 I have had Serana wearing a full scaled armor set including helmet, and I have had her wearing armor with no helmet and no hood. Just because you cannot use console commands to get her to wear what you want her to does not mean it is a bug.

That isn't even what I said, please actually read things rather than skimming over them.

If Serana was no supposed to wear any other armour, she would not be able to equip anything, but she can, and does, so you are clearly supposed to be able to upgrade her armour and weapons the same as with any other follower.

If I use console commands to remove all of her items, she loses everything except her hood, which is not supposed to happen (I also get error "BAD EDITOR" messages if I check her inventory, which means there is something wrong with her armour, because those error messages are not supposed to appear), and if I then give her the armour I want her to wear, she gets her default armour back and wears that instead. She will wear the Hooded Thalmor Robes, but she will not wear a seperate hood and armour piece, and she will keep equipping and unequipping all the other pieces of her armour seemingly at random, rather than keeping all her given armour on like all other followers do.

Clearly she is bugged, and needs to be fixed, and just because you have not had said bug, that does not mean the bug doesn't exist. After all, I don't have brown eyes, that doesn't mean people with brown eyes don't exist.

Don't think there is one and this isn't really the appropriate section anyway. There's plenty of unofficial bug lists in the support section though.

http://www.gamesas.com/topic/1396549-dawnguard-bug-list-2/

One of the things I finished first was Sorine's crossbow schematics. After I got my newly minted Enhanced Dwarven Crossbow, I asked around for other side quests. I got told to talk to Gunmar and Sorine, now I have a talk to Sorine about improving crossbows in my misc quest list. This is impossible, since I finished it. She will tell you to talk to Gunmar.

Serana not only can infect the player with vampirism during combat, it doesn't behave like the normal infection! You receive no warning message "You have been infected..." nor a three-day waiting time during which you can cure yourself with a potion or using an altar; it happens instantly! The first time it happened to me, I thought maybe I'd missed the warnings, somehow, though that seemed strange. Since then I'd been keeping an eye on my Active Effects, just in case. The second time however during a big fight with many Dwemer automatons it kept happening and happening and I got frustrated and dismissed her. At this moment I *hope* it was related to her and not something that happens randomly because that would render the game unplayable for me...as opposed to just unable to have Serana as a companion if I don't plan to have my character become a vampire :/ I'm quite annoyed by this, and I'm not even certain it's triggered by her spell hitting me, or simply her using it while in my party.

ETA: I found out what the problem was: the vampire blood potions reset the player (and only the player) to a stage one vampire, regardless of whether they are supposed to be one in the first place, and regardless of who drinks them. Serana using the potions in combat caused this issue. :I

The second major bug I encountered was during Kindred Judgement, on the Dawnguard side. The Dawnguard were ready to assault Castle Volkihar...except the main gate would not open, and said it required a key so it could not be picked. No vampires poured out to attack either, only the Gargoyles triggered as they were supposed to. Reloading or restarting the game did not fix it. I did manage to get the gate open (and two more doors afterwards) with the console, and then the quest proceeded as normal, but still.

If that's truly the cause of the bug, I think I might love you forever for solving that for me.

It is; a friend of mine checked how the potion's effects worked in the Creation Kit (which is how we find out in the first place) and the problem went away once I removed the damned things from her inventory. Non vampirism-inducing adventuring ensued.