They were SUPER close to releasing Buckingham Nicks back in 2012/2013. This interview shares both the perspective from both of them. There seems to have been some kind of disagreement with what to do with Without You.
I kinda get the impression that Stevie wanted to throw it onto a Buckingham Nicks re-issue as a bonus track, do a few shows, and kinda cram it into the year that Fleetwood Mac would have been touring in 2013. Lindsey wanted to wait and do it right and not rush through it. Lindsey seemed thrown for a loop that she shows up with a long lost Buckingham Nicks track she wants to work on, yet wasn't open to working on any Fleetwood Mac material just prior to the "get together" they had to work on "Without You"
https://www.rollingstone.com/music/m...od-mac-233617/