"iTunes media folder location" keeps reverting to local storage instead of persisting the NAS location, how to stop this? I have my iTunes music held on a NAS box and apart from severe lag times, it works fine, however, occasionally iTunes just switches the 'media folder location' back to the local machine without even asking me.
The wifi connections between iMac/NAS/Router are fine and are always available.
How can I prevent it from automatically switching it back?
Put the iTunes itl file on the NAS along with the media.  Then lock the copy of the file that's in your $HOME.
Launch iTunes.
iTunes will whine that it can't open the library (it thinks it needs to write to it), and will ask you for another.
Point it at the one on the NAS.
Now, iTunes will regularly, as you know, try to revert back to the one under $HOME.  But now it can't, so if it does, you get the prompt, and can redirect it.
Instead of discovering some time later after it's been storing media on the local drive again.