Wait, so the attacks DO stop after you complete the Dawnguard MQ?!

I haven't downloaded it ALL THIS TIME because I had thought they just continued forever, without stopping!

Unless you get hit by a very rare bug, yes they stop.

wow, bethesda still kept these in? and they are releasing more add ons before sorting this out. its a real shame, i havent played skyrim in months since the first dlc's release because of these attacks. at first i thought it was pretty cool, until the stables outside whiterun were attacks by hellhounds and master vampires, i then realised how much of a problem it was because i reloaded my game well over 10 times to try and prevent any deaths. i wish i could play skyrim without feeling uncomfortable, i was 20 hours into dawnguard too