I was in Blackreach and Lydia just stopped and no matter what I did I couldn't get her to move. Even going through doors didn't work. Waiting didn't work. I had to load a previous save and leave her on the elevator.

Anyone know why this happens and what you can do about it?

p.s. Since I've left Lydia home, and used the steed stone to compensate for the lost carrying capacity and I must say it's kind of nice to be able to climb rocks like a billygoat without worrying about my follower being able to follow. Kind of freeing.