So I just finished Namira's quest and went back to Whiterun to do the "Purity" missions for the companions.
I started with Vilkas, he followed me when I fast travelled to Ysgramor's Tomb but didn't follow me inside.
So when I went back outside to retrieve him I noticed he wasn't following me, so I look at my active quests and "Purity" was under completed quests even though nothing had been done.
Now outside of Ysgramor's Tomb I ask Vilkas for work and the process repeats.
I go inside, he doesn't follow me, I go back outside and the quest is once again completed.
Third time I attempted the quest remained active but Vilkas still refused to follow me.
This time when I ask about work I was given one of the radiant reoccurring quests.
So as a last ditch effort I ask Vilkas to follow me to see if I can kick start the quest only to have him say "It looks like you've already got someone with you"
I have no followers, the only thing I can think is my followers designation got bugged during the Namira quest.
I'm also assuming that this bug is what broke the Purity quest
Does anyone have any form of resolution to this situation?
I'd really like to be able to fix the Purity quest line as its important to the RP of my character.
Any and all replies are appreciated!
Oh BTW I'm on 360 or I would have just asked for a way to fix it using console controls........

If you don't have an earlier save to revert back to, make one now. Start experimenting with ways to get around this. Here's a few things I would try.

• Deselect all of your active quests except the one you are trying to accomplish.
  
• Have Vilkas follow you into a different location that brings up a loading screen. Then outside and back to Ysgramor's Tomb and try again.
  
• Ditch Namira's Ring, if it's in your inventory?
  
• Tell Vilkas you're letting him go. Then tell him to follow you again before he leaves.
  
• Tell Vilkas you're letting him go. Find a different follower, let the new follower go. Then go have Vilkas follow you into Ysgramor's Tomb.
  
• Go back to Namira's shrine?

Good luck! Tell us how it goes.

Try going in without Vilkas and pushing the first lever you see(in a certain room where your progress is blocked by a gate). That should update his AI and then you don't really need him for the rest. I'd save before you do it though.