Only version 7.1?  why no later updates?! :)

Hm your atmosphere settings are odd, but recreating them in 7.5 infinite I don't have any problem even so (though I can't adjust "Light colour" due to changes in version),sodoubt it's the atmosphere setting.

why on earth is it showing black even in the preview window?! eyebrows arch to top of his cranium! :P
 Weird!!!

Does it always show like that, black, or only sometimes asyou note? Does it occur after you've had Vue running a long while? or, if you have a laptop...could it be overheating?
puzzling though posisbilities

try making a new scene with a default atmopshere
make a sphere
edit the material, right click, RESET material so it should be a grey
edit reflectivity, set to 70%, does that work ok?
if it does work ok, and if your older materials don't work ok consistantly, maybe the old materials have been corrupted?
sorry best I can think of at the moment :/

OR
wonder if it's a fault witht he display settings? does it occur if you turn off "Enable Background Draw" ?
:)

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