Yes, it's a bug . It happens to me when i go into an editor of special effect where there is a preview (motion blur, blur, light cone ...) . If i don't wait the preview to render before i click OK, then i can't render the scene anymore unless i restart the prog :( . So, go back into your special effects editor, and wait for the preview before you click okay, and see if it works . That's for sure a silly bug, and i don't remember it happened in version 1.0 . It makes me remember that i got to inform Eovia about that ! By the way, for all your bugs reports, the address is : http://www.eovia.com/index.htm?support.htm&0 Hope it helps, litst