Question: how to reset ddj sx2?
Answer: Disconnect the USB cable from your computer. ... 
Press the [STANDBY/ON] switch on this unit's rear panel to set this unit's power to standby. ... 
While pressing both the [SHIFT] and [PLAY/PAUSE ] buttons on the left deck, press the [STANDBY/ON] switch on this unit's rear panel. ... 
Press the [KEY LOCK] button on the left deck.