Mental Ray render turns black
 

Hi,
I've been trying to test render a cube and while it starts out fine, shadows and all look normal, in the final pass it turns all black and outlines the shadows and edges of the cubes and adds a grid of red lines at the back. I may have selected an effect by accident, but can anyone tell me how to get it back to render properly?

Thanks!

can you post a screen shot...........dave

Just fixed it... Not sure what it was, but I reset all the settings to default and started from scratch. Works fine now!