ALAC Files USB - xdj-rx3 - Rekordbox

Hi 
I have troubles as I renewed over half of my mp3 files into ALAC (converted them from FLAC to ALAC).
When I play them on rekordbox there is all working perfectly fine. (as well when I connected the computer to the Xdj-rx3)
Now I loaded them with all other tracks through rekordbox on my USB. With mp3/AIFF it works but all my ALAC Files get the message on the xdj-rx3 format not supported with the Code E-8305. 
I cannot understand - any suggestions? I makes me crazy as I did so much work ripped for more than 100 hours etc or converted......)
Thank you so much for a hopeful easy solution.