My Tunes have been the center of the Universe for me and from day one of iTunes and all great stuff that's no more, I learned to trick these Apps even AppleTS didn't know if you could. The only way to keep your sanity. In a new install or post hammer reinstall I would fire up the new install, find where it put the Music Library, mostly the same place for ages so really no need to look. Then "Alias" the Remote Library, even from a NAS, folder into the iTunes System works in the OS Hidden Library. That way I could keep my Library on a separate drive so when the OS hammered as it did and does, my Music Library of many Decades stays safe.
Then as Apple started to take more control besides the Music Library the original directory that held all the what and where changed from an .html to .itl and became the cornerstone and key to acknowledging that you even have music and whatnot is on your machine. And with that it seems Apple got it that either we didn't want our Libraries on the same drive as the OS, not enough room or wanted multiple Libraries is when they enabled the ability to find and select the Directory Folder. But the kicker is the .itl file to get things back as if there was nothing changed. The same with Photos. Most of the time. If the .itl file wasn't there or got corrupted it is enough of a reason to have a mild heart attack . . .
