I just upgraded to SFML 2 today.
I can't get my old music ogg files to play at all. It doesn't matter if they are loaded from memory or file. SFML puts "Failed to read sound file from memory (Supported file format but file is malformed.)" into the std error stream.
Is this a known issue? Like I said, these files played great in SFML 1.5 (And the svn version).