Volume Scatter Turns Everything Black

I am creating a map for a game I’m working on. I scaled a cube around my map and added the volume scatter node to the cube (It is connected to the Volume of my material output because I know that is the most common fix). When I turn on rendering in my viewport shading everything goes black. The density is 0.100 the color is pure white. I have a sun lamp outside of the box with 80 strength and pure white emission. I’m just really confused with this. Thanks for the help.

Extra Information that may be relevant: Sun is .100 in size, 1024 bounces, Cast Shadow and Multiple Importance is checked.
The map is quite big (X: 1037, Y: 1054, Z: 148).
The outside of the box is a weird bright with blackish/greyish pixels.
I’m using Blender version 2.78

Turns out that my volume scatter box was too large and was only spreading the light at the very top and wasn’t reaching the mesh more towards the bottom. So I turned the density down to a really low number, .0002 worked for me and it shows up like fog through the entire mesh.