I know this is probably futile to enquire, and it's not the first time I've mentioned it but...
Does anyone else get this:
They work using vray RT on a scene and then it just dies and will NEVER work for that scene again - ever. Start a new scene, no problem. But as far as RT is concerned, it's out to lunch until you start a new scene.
This happens 100% of the time and it KILLS my production time.