So I summoned the unbound dremora, but when I killed it just became a lootable corpse. Now I can't resummon him and therefore can't complete the quest. This means I can't get the master level conjuration spells. Seriously I don't get how you guys allow game breaking bugs like this out. To be honest, while this game is great the number of bugs and freezes I have gotten is just unacceptable. I'm not buying another Bethesda game again. Its just not worth putting so much time and effort into games just to have them break.

I have had this same problem. I tried reanimating and dispelling his corpse in an attempt to reset reset him, but nothing has worked.

Same problem here. Other forums said that it's because you have followers with you while you do it and they kill it before dialog can complete. Hopefully the new patch fixes this