Been having some Dawnguard issues that I am sure are mod related. I thought it might be a good idea to have a thread where people can list any mods they find that causes a conflict or issue with Dawnguard. I think it would be very helpful to have these all in one spot rather than trying to hunt them down through all the troubleshooting threads.

I'll start first. I was having a problem with ctds when I tried to shout with this mod installed. Uninstalled and now no problem. With that at least.

http://skyrim.nexusmods.com/mods/3799

Some mod compatibilities may be hard to fix right now, since we did not get the updated/modified and new script sources with Dawnguard. Here's hoping Bethesda will release them soon. For example any race mod that depends on RaceCompatibility.esm will probably have issues.

Imps more complex needs makes it impossible for me to feed on npcs that are not sleeping. Because of this I was unable to make the moth priest my minion, no feed option was given after using vampiric seduction. Disabling the mod fixed it.

Thanks! This is the kind of info everyone needs in order to help troubleshoot their game. Especially people using a ton of mods like I am.

Also it seems there is a quest/dialog related bug that may rear it's ugly head for some mods and even in some vanilla and DLC content: http://www.gamesas.com/topic/1399783-dialogue-no-longer-works/.

I can't tell which mod it is (or if it's a mod) but something is messing up animations. For example, I can't go to 3rd person with a Crossbow equipped. The same is true for mounted combat, my character just stands up haha. Also, the animation for the Moth Priest reading the Elder Scroll doesn't appear, only the dialog, then the quest stops b/c the priest is "busy".

after the last update when they added mounted combat i found out that some mods that add animations can cause the standing up when trying to fight or go through water on horseback

Yep, the standing on horses is animation mod related. Finally go mine going. Kept having random freezes until I uninstalled UFO. I am going to try it again later but for now that fixed my problem.

Here's a couple more that cause problems:

Followers can relax (tell Serana to 'wait' in your house, and sometimes you lose dialogue options and she stops following you completely)

Give a dog a home, in fact, any of the dog mods I find conflict with her, including the armoured dog mod.

Horses for companions and Better companions. For some reason, I ended up with Serana, a dog, and three horses following me around.

moth priest animation problems as well as him being "busy" was fixed in my case by disabling animated prostatution mod.