Melodyne Assistant and Cakelab problems. Sonar Platinum ok (Solved I think)

So, did a show and tell for a client the other day with Cakelab's latest update from 6.30.18 (which by the way has been working great.) However, after recording his vocal showed him how I can fine tune the pitch and Melodyne crashed and left me "hanging" literally. Tried on two projects and same problem. Loaded up the songs in SP and all was fine. Think I should re-install Melodyne? Any other suggestions or anyone else having this problem?
 
Edit - moved the latency from 128 (2.9ms) to 512 (11.6) and it seems to work ok. I keep my latency really low for tracking but need to remember to switch it back up for processing.