Sharing iTunes Library Between Mac & PC Via A NAS

Solution 1:

The problem is that the underlying structure does not yield itself to being easily shared. Here's a similar issue with the problems explained: How to setup an iTunes library to use between two Macs?. Any chance one or more existing iTunes clients were open when you tried to add the MBP?

Solution 2:

There's a better way to share an iTunes library between machines. Simply turn on Home Sharing in iTunes, this works when the iTunes library is on a machine in your network, with this switched on, other iTunes clients on other machines can see the same iTunes library.

If you want to keep the library on a NAS, thats a separate issue, I think if you google for that you will find that the process is basically the same as putting the iTunes library on an external drive on the machine.