Reply to S2 MK2 crashes every time

I never had a problem with S2 MK1..
Now with S2MK2..after 1 or 2 hours play, LED freeze, music crashes (suddenly stop)..it happens every time.
I just installed 2.6.6 update. I was hope this will fix this problem.

But after last evening , sound crashes after 2 hours play. No sound at all while traktor on my mac still working. I had to switch off the S2MK2 and switch it on again and sound back to normal.

I love Traktor S2, but this is frustrating