I have my entire iTunes media folder loaded on my MBL and had been using it this way for over a year with no problems. I use my PC to access iTunes from the MBL. PC, MBL, and iTunes all have most recent versions installed.
Recently, when I download an app update through iTunes or burn a CD into my iTunes library, it does not “appear” in iTunes. I know it has been saved on my NAS though. For example, if I burn a CD using iTunes, it will not show up in iTunes in my music library, but I can find the file manually by searching in my iTunes directory saved on my MBL. Also, I use Sonos (a music device that is also connected to my network and accesses my NAS) and am able to play that CD through Sonos because it is recognized as music on my NAS. Another example, I recently updated 30 apps for my iPad through iTunes. The next time I loaded iTunes, it did not recognize that I had already updated the apps, and showed the same 30 updates as needing to be applied again.
Any help would be appreciated. I don’t believe this has anything to do with iTunes 10.7 or iOS 6, because this issue has been occurring for about 4 months.