I have an extensive music collection that I keep on a network drive. Out of the box, the music app doesn't work with network locations. I've so far "tricked" it by using a symlink to the network share, but things are still behaving strangely.
It has pulled in most of the music, but a lot of it is still missing. To top things off, it will only play cloud versions of songs rather than the local versions of things that it DID find. I even tried to manually load one of the files it couldn't find, and it wouldn't play the file and gave an "unrecognized file" error.
Keep in mind, the Zune software works perfectly with this setup, and gives me no troubles (and will play the file mentioned above w/o issue). Why is the Xbox Music app so flaky with this stuff?