I hope you can get a good answer on this.I can play FLAC audio with no problems on MP17.
I archive all of my music that I got from CDs to FLAC and keep that as my digital archive for my music.
I also encode my Flac audio to Ogg (Q6), as well as copy those Ogg audio files to my Cowon portable media player as well as to my
Samsung Tab. ,
While on my computer, I play the losless Flac.
I don't have a problem with this, but I was wondering if you uninstalled and re-installed MP, if that might fix things for FLAC.
The fact that it plays FLAC on VLC (which I have as well), I think is a good sign. It tells me that the Flac files are not corrupted.
I have used MP for so long, I don't remember having to download a Flac add-on.
In general, Flac codecs can be found here
http://rarewares.org/lossless.phpat rarewares, where you can find the latest versions of codecs and encoders.
I hope someone from J River gets you an answer. Anyone who is playing Flac is a smart, resourceful person.