I have a DS212 running 4.0. Playing music is a key goal for me. I have about 2000 CD's stored as FLAC files, but I started with one album as a test. The tracks show up, but if I choose a track and press play, no movement happens and after a few seconds the Pause button turns back to a Play button. I tried uploading a low-res MP3 file, and that plays fine.
I read about transcoding, but either my model does not support that or it has been eliminated in 4.0, as there is no reference to it in the Options menu. (Also, some people seem to have FLAC working).
I originally was trying to run Logitech Media Server, and everything was incredibly slow and timing out with lots of error messages to the log file, so I thought I'd start with Audio Station as a simpler solution. I currently run Logitech Media Server from my desktop computer and everything works like a charm. I have a gigabit Ethernet connection, and file uploads are extremely fast, so I know that's not the problem.
Thank you for any help.