So, my quest log says I have completed 15 of the Daedric Quests, but I did not get the achievement. Am I supposed to keep all 15, or do I not get it because I sold a couple of them?

did you use god mode during any of them?

I think during the Hircine quest, if you chose the wrong one, it won't count.

I forget which, however.

Also, the Skeleton Key doesn't count at all.

I'm trying to get this achievement too, has anybody got it and can clarify?

I had 14 at my house in a chest and the last 1 on me and I got it.
I know you can screw it up easily though, I did on my first character.

So, I think the reason I screwed it up is because of Mehrunes Razor. I didn't kill the guy and therefore didnt get it. Which svcks. I guess I need to start a second game and do them all over again.

Also, I am playing on an Xbox, so no console cheats for me...