I followed this article and deleted my two older previous libraries files and left the latest one that was a month old. I still have my artist and albums with artwotk in my NAS drive but cant see any music files. But they still play on Sonos, help!

I followed this article and deleted my two older previous libraries files and left the latest one that was a month old. I still have my artist and albums with artwotk in my NAS drive but cant see any music files. But they still play on Sonos, help! They also play from the NAS audio software, but I can't see them in the folders, I'm scared to try itunes Match and also my source directory in iTunes preferences/advanced is now blank, but iTunes also still works playing tracks. Help!