I have had MANY problems with quests on the thief's guild, even before I started it I was warned about it and I saved before and after every quest, just to make sure. and I REALLY ended up needing the saves, i finished it eventually but now I'm stuck on Repairing the Phial and i have everything but it says I don't have the Briar Heart, now I'm stuck with a quest. Also when I save in my Markarth home and quit, and go back on i have to reload the save because everything in the house is gone, i feel like I'm in fear of loosing the stuff in my chests. This is a masterpiece of a game, don't get my wrong, I Pre ordered it. id go so far as to say its my favorite. I just feel like I'm playing the beta of it. please fix the bugs Bethesda:/

Do you have the Briar Heart in your inventory? If not then get it in there, if so, eat it and buy another one then try again.

The briar heart was a pain in the [censored] for me and I had issues completing this quest. You cant eat a quest item either. I also think you have to go get a briar heart AFTER getting this quest because I had problems until I did this and then it worked fine but I could be wrong here. If you have a problem with this quest or after completing it dropping or storing briarhearts you can easily fix it with the console.

player.showinventory lists all your items and you can delete items that arent removed by a quest like briar hearts, drums and flutes etc with player.removeitem itemcode 1

These small annoyances are usually fixed by either a bethesda patch or a community patch.

After typing this I have just realised this is an xbox complaint and I wish you the best of luck but will leave the post for pc users who read your complaint via view new content or search function and have the same problem.

Only quest i've had a problem with is the companion's quest where I have to return Aela's shield to her and she is nowhere to be found, shes not fighting giants or at jorrvaskr. It kinda pissed me off to the point where I just stopped playing altogether, but my brother has had no problem with the companion's quests and its on the same copy of the game and the same xbox too, and I think it helped him out a lot as he is about 6 levels (im level 26) higher then me, has a house, and a lot more gold, he is farther in the main quest though.

i cant eat it, and i already killed the guy i got it from before i got the quest, unknowing, its not a big deal so it doesnt ruin the game at all, just kinda annoying.