For some reason all of the sudden the interactive rendering will not update.
If I make any changes to lights or materials, it just starts calclulating the lightcache over and over, never stopping.
I have to stop the rendering and start over again 
The issue started with Vray5 hotfix 2, updated to 5.1 but that didnt solve the issue.
Any ideas?
Ok found something…seems to be a bug from anima. If I delete all characters everything works again.
Will try to find out why