When I purchased sonos, many of my i tunes music files would not play because the i tunes purchases I made pre 2004,5 were incripted. I joined apple cloud program, deleted my files and pulled in new versions of tracks. This the problem. In the last day my imported files from i tunes in sonos show the track name followed by a code: m4a. Sonos now says unable to play as the file does not exist. So frustrating. Please help Sonos?