rekorbox crashes / XDJ-RX waves freeze

S/w keeps on crashing. It is really frustrating. Even after an update (4.1.1 on early  2011 macbook pro w/ El Capitan 10.11.4) it keeps on crashing right after i open it and before hitting on a playlist or anything. It is has become really annoying, cannot do my work with ease. 

XDJ-RX: Sometimes it's like it is getting heavy on memory or smthng and the waves on the screen are going with pauses....start-stop-start-stop.... Is there a trick on the unit to clean cache memory or something?