RekordBox Dj 5 freeze when music loads

Hi guys, i have rekordbox dj 5 and i use it with Pioneer DDJ-1000

when I have deck 1 playing, load music to deck 2 and then freezes and you can hear the gap on the output sound (club sound system).

When I play, I close everything even wi-fi, antivirus etc. 

I work with a macbook.

Thanks