I have an even more weird situation:
Updated to Yosemite and iTunes 12.0.1.26
My movies are saved to a WDMyCloud network drive. I have both a MacBook Pro and an iMac connected to the network. On the MBP, iTunes works perfectly. On the iMac, the following incomprehensible problem:
1. The movies are added easily enough.
2. I am able to add all info (Title, genre, year, etc ...), except:
3. When I add a .jpg file for the artwork, it does not load.
4. And when I try to add it again, iTunes does not 'see' the network drives (although they are visible in Finder).
5. When I quit iTunes, and restart, it sees the network drives gain, but then the problem starts for 1 above, all over again.
Go figure.
Any suggestions would be most welcome.