I am having a problem with building my lighting for my map. When I click the lightning bolt to update, it processes for a split second and then stops abruptly without very poor quality lighting. This happened very suddenly with my map and I can't think of anything that I could have done to cause this. I've tried grabbing my sun and sky volumes from other maps as well and it still happens.
I've checked around the internet and I could only find 2 instances of this happening to other people but they received no help with the problem.

there is different modes aswell, like ingame-mode lighting and editor lighting etc i dont have the program and even if i did, i still forgot what the defaults are since i rebinded all the light toggle stuff to my num-lock numbers to switch between them on the fly while mapping, have a look in the bindings to do the same