I have a music library of 3,000+ songs. Some of that was tagged properly, some of that was TBD. About 6 months ago, I was researching a way to make this easier and downloaded a program called MusicBrainz Picard. Apparently it was supposed to automatically tag all my music by its digital audio fingerprint. Sounds great! However, there were a couple of OCD rules I had when tagging my music, and after running MusicBrainz across my entire iTunes library, it was apparent that my rules were not being observed. First, I want the year the song was first released in the Year field, and I don't want the greatest hits version of the song, I want the song on it's originally released album or single. Without this, I can't make a smart playlist of 90's music without getting 60's tracks that were tagged by the compilation album they showed up on in 1994. Other than that, I'm not really that picky. Album art should be there if possible. Anyway, MusicBrainz messed this up. What's worse, it started messing up my folder structure, and started nesting folders like the Land O' Lakes butter lady in some cases. I stopped what I was doing and said I'd go back and fix it later, but other things were more important. I had curated my library quite well up through the letter "G" before I did this, and now I'm staring at a huge task - and I'm not even sure where all the problems are. I noticed this morning (I've been shuffling the "Music" folder around several Macs as this has been an upgrade season for me), that there is a "Previous iTunes Libraries" folder within this "Music" folder. I'm intrigued as to how this might be used to rollback my music library to something before the MusicBrainz experiment. Since iTunes Match came out I've been taking advantage of it, but using iTunes to expand my library instead of the legacy methods I used to build it in the first place. So I'm confident that if rolling back to an old library is necessary, I won't lose anything since everything that's been acquired since then has been purchased through iTunes. How would I go about rolling back to a previous library, would it even help me fix folder structure and ID3 tags (I'm suspicious that it wouldn't since that metadata is stored in the files themselves), and are there any gotchas I need to look out for if I go down this route?