Thanks everyone, I uninstalled and reinstalled Vue and guess what? It works again! This is the 2nd time I've had to do this though, so I guess it's a quick fix. Hopefully having set the virtual memory to 3Mb will prevent it from happening again. JC- you could be on to something with the heat issue. I'm running Vue on a P4 3.2GHz HP 7000 laptop and it runs VERY hot. I typically keep it lifted at the back while working, but if I'm rendering overnight I leave the vents overhanging the edge of the desk. I downloaded Registry Mechanic, so we'll see if that helps stabilise things. Thanks again, Jackson p.s. attached is latest rendering, medium radiosity quality settings.