Under New Management won't start.

[Da_BossMaN69]

So this one has been driving me up a wall recently.

I've completed the Thieves Guild questline, collected every item from the TGMQ, completed all side jobs and reputation quests, even the quest for Tonila and the Khajiit caravans, yet I can't activate the quest.

I head to the Thieves Guild, go in via the door under the tomb, and when I talk to Byrnjolf he just talks about retiring, and vaguely mentions me becoming the new guildmaster and then leaves and says he's busy.

So what gives, Am I SOL and can never be named the guildmaster or what can I do? What am I missing here, I know 100% I've done the reputation quests, Delvin even did the whole "You're the best damn thief" when I completed the final reputation quest.

[p-sto]

Apparently bugs for this quest starting are fairly well documented, though it's possible that none of the fixes are available to you. Still take a look and see if there's anything that might work.

http://www.uesp.net/wiki/Skyrim:Under_N ... ement#Bugs

[Da_BossMaN69]

I did the side quests before completing the Main One. I'm aware of the running outside one, though nothing occurs.

The quest simply doesn't start, and I'm unsure how to trigger it, Karliah is nowhere to be found, so I can't see if talking to her solves anything.

There's no chance that new patches are coming to fix issues such as this one right?

[p-sto]

I'm guessing you're not on PC so the console is out. I would try a variation on the Sapphire fix and see if initiating the reparations quest will fix things. Attacking someone in the guild would be a problem because it's so crowded there but Maven Blackbriar counts as a member too and she should be easier to isolate. Obviously save before you try but I think attacking Maven would likely be your best bet if anything is going work.