This is a comment that I began to post on the 1.2 Patch Bethblog entry, but comments are closed for whatever reason. So here is my input:

Karliah is stuck in a Winterhold bar cellar and won't return to the Ragged Flaggon (in Rifton) for the theives guild quest. As a result I can't use any fences, return 'unusual gems', or finish the end of the Dark Brotherhood questline. This is an amazing game, but I'm pretty upset that I'm a level 32 Theif/assassin that can't use the Theives Guild. Considering that's 80% of what I do endgame, stealing and all, there's really no point in me playing more until thats fixed.. I'd make a new character, but for all I know it'll happen again, and that'd just piss me off.

So here's hope to Wensday, hopefully it'll unjar Karliah and I can continue enjoying this technological masterpiece.

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I also posted on Yahoo Answers about it soon after launch when I encountered the problem. Here is the discussion:
http://answers.yahoo.com/question/index;_ylt=AjnHGJMlIKvlvutcHv._RtLsy6IX;_ylv=3?qid=20111115114224AAuSR4t

(I have no idea why the Bethesda employee responded discussing werewolves? I found that odd..)

Has anyone else here experienced this? It's quite annoying.. I'm praying that the patch fixes it tomorrow.

I know I can't be the only one with this problem..

I don't want to annoy anyone by bumping this, but i'm level 35 and I'd like to start the thieves guild.. I have a feeling I'll have to start a new character, but I'd really rather not.

Someone just let me know that my problem's been logged..

I have the exact same problem with Karliah stuck in the basemant instead of going to the ragged flagon. (PS3)

It happens if you do some side quests in the interim (i.e.you need to travel to the ragged flagon straight away to stop this occuring).

There is a fix for PC but not for console.

Its ruined the game for me - I do not want to return to an old save created 20 hours ago.

PLEASE FIX

Try using unrelenting force on Karliah to give her a friendly nudge.

It worked for me when Esbern and Delphine were unresponsive on some quest. Different circumstances, so it probably won't do any good. But you can always try.

I'm level 42, completed the thieves guild missions (i'm the guild master) and I can't use ANY of the fences.. there is obviously a big problem with the thieve's guild.. it does appear they fixed the armor problem (I waited for the patch before becoming the guildmaster, and Tolinia just gives you a new set of armor now).. I'm really annoyed as I have a house full of stolen goods and I can't move anything..