Doubleclick to an autoplaylist, i.e.: Format: FLAC && 5 Star rated.
Select all files.
Rightclick -> send to -> Format Konverter
It shows you a few files which shall be mp3 and cannot be converted to mp3.
But if you nail this down and i.e. only select 3 FLAC files, then the same happens.
If you want to convert these FLAC files to FLAC, then the files are selectable to convert (which makes ofc no sense).
FLAC to mp3 conversion entirely doesnt work.
Thanks upfront and hope for a fix.