I tried looking around but I didn't see anything about this, so maybe it's just my game...but I'm having a big problem with the Companion quests. These are the ones after the main storyline ones that get you the achievements. I just updated to 1.5 seeing that Farkas was supposed to be fixed, but my problem persists.

Ok, So I go to Farkas, and ask about a job, he tells me I'm already on one for Vilkas. I look through my journal, and there's nothing there about any job from Vilkas. So I ran on over to Vilkas and ask him for work, and he gives me the quest to fix his lycanthrope. I agree to it, and get the Purity quest. I go to leave but Vilkas doesn't move. I track the quest and head up to the tomb to cleanse his blood. Once inside, the quest is gone from my log altogether. VIlkas is no where to be found.

So...I leave the tomb and head back to Vilkas, whose still hanging out at Jorrvaskr. I ask him to follow me, but he says "It looks like you've got someone already" which I don't. The first time I tried this, I sent Lydia home. This last time, my last companion was the dog, but he fell in battle and is dead. So I don't have anyone with me at all. I go ahead and click on I'm Looking For Work and now he gives me a whole new quest about rescuing someone whose been kidnapped.

It seems like I completely missed Vilkas' Purity quest and all of the Companions, think I have a companion with me already, when I don't. So I'm wondering if this is a known glitch, if there's a fix for it, or is it another in the list of things Bethesda needs to eventually address. Thanks for your time.

Oh, I thought I should add, I had the Escaped Criminal quest awhile back, and never was able to find the criminal, than in 1.4 that quest vanished altogether. It's in my quests completed log, but the objectives remain unfinished.Maybe that's the problem? Maybe my problems are just stuck on this character but won't happen in a new one?

Try accepting the Purity quest while Vilkas is outside of Jorrvaskr, as in ask him to follow you, leave, dismiss him, then ask for work.

He never leaves Jorrvaskr. Never moves from just inside the door leading out of Jorrcaskr. He just stands there and he won't ever follow because he always says I already have someone following me [which I don't.]

I am having exactly the same problem - exactly as JaseDakota describes including the Follower glitch where he sys you already have someone when you don't. As soon as I leave Jorvaskr the quest moves from the active quests section to the completed quests section. I tried going to the Tomb anyway on my own but it won't let me chuck a head in.

It's aggravating because it took me ages to actually trigger the darned quest in the first place (didn't have the heads in my inventory and ended up doing about 50 of the go kill quests trying to trigger it.
I was thrilled when it did but quickly deflated when hitting this whole new problem.

So if anyone has had the same problem and found how to workaround it, rather than educated guesses, please post here. Bet loads of people having the same problem

I managed to get myself cured - but still lost the Cure Vilkis quest. I'm going to revisit it in a couple of days and see if I can find a workaround, but my main objective was the werewolf cure for my elf, so at least I got that.
What I did.
Removed heads from inventory.
Got a quest from Vilkis - told him to follow me.
Retrieved the heads.
Went and did his quest.
Turned it in to him at quest place.
Dismissed him then immediately clicked on him to aask for a job.
Got Purity quest.
Asked him to follow me - got the 'you already have someone blurb'
Zapped solo to Tomb.
Activated the fire - THIS time it took the head.
Out popped my wolf spirit - killed it - cured.
Left the Tomb and bam, the cure Vilkis quest moved into completed quest section.
So that part of the problem still remains - any ideas?

From another Topic on these forums I found that if you cure Farkas first, then you can sucessfully cure Vilkis (and yourself).

Summary: Do a radiant quest for Aela, Farkas and Vilkis. Have the Witches head/s in your inventory. Ask Farkas for a job, cure him. Repeat with Vilkis. Cure yourself.
Note: when you ask for a job it is when they are sat out back by the training dummies that they ask you to help cure them.

No idea if Aela ever asks for the cure - can't trigger it or find any info on it - been struggling with Puirty for so many days now, don't actually care lool