To both Adriano and Walter I’m afraid the answer is no (but you guys both have cool names!)
My comp is not set to draft mode and the lights are set to a normal 100% intensity. It’s a really strange problem and it just got stranger…
It started happening in the middle of a project and I’ve found that if I add a new light via a menu it makes everything black no matter where I position it or what type of light it is. However, if I copy a light from a previous composition (where the lights are working) to the current problem composition, they will work perfectly normally.
So…i basically have no idea what’s going on, it’s really weird. I explained it to a fellow co-worker/after effects user (in real life) and she couldn’t understand it either. She did nicely title the problem as “Devil lights” though. hehe
I thought perhaps it’s something to do with rendering but then I don’t understand why a copied light would suddenly make it work.
Anyway at least i’ve found a workaround for now.