VST Dropout

I have Cubase 8 pro with the latest update .10. I am running an I7 quad core PC with 16 gigs of memory. When I load some VST combinations such as Omnisphere and Cinematic Strings together, one or the other randomly drop out or crash, sometimes crashing Cubase itself.

I tried creating a track then rendering in place to see if it frees up memory but the render track has the dropout included. i’m running Cineatic strings through Kontakt 5.3. Anybody else have this problem?