Sonos "loses" ability to access music library every few days

This is frustrating to the point where I am probably going to have to return the system. . .every few days I try to play some music and I get the "access denied" message from Sonos. It won't play anything from my library (which is local to my Mac). I delete the library and add it back and it will work for a few days. Nothing changes (network, system name, etc) but it will stop working.

Any ideas? Sonos support has been minimally helpful.

Adam