I just got a Rumours rehearsal cd not too long ago. I have to say this is the absolute best live version they ever did. I was surprised to hear Stevie doing the original harmonies that were subsequently left off of the final recording. Lindsey also does harmony as well.

It seems as though they rehearsed it with the full vocal ensemble and then canned it before the tour even started. I don't know why. I know Stevie was still on stage during that song, at least during the first part of the Rumours tour cause i can hear her playing that trap instrument in the background.

I've been listening to this version and i get chills when Stevie and Lindsey come in on the harmony....There's a certain point where their voices blend together so magically that it almost creates a single voice in itself. (if that makes sense).

I think the rest of the versions are pretty boring without the backing harmonies.