BPM changed crossfader not fully functional DDJ Flx4

how do I restore the initial settings, because after I upgraded...my flx4 function isn't like before...when a song is played, if I put a song on deck 2, with the smartfader on, the song being played immediately changes as well as the song I saved on other decks....if you slide the crossfader it doesn't work optimally...thanks for the info...