Hey guys it's sorted! Thanks so much for your help. I disabled ENBboost and the fog went away. So I played around a bit and remembered I think I overwrote part of the dll when I installed SMAA which of course requires a second dll. I didn't really know how to use both at the same time so after accidentally overwriting them, I remember attempting to do some weird fix and... clearly it didn't really work :P I deleted all trace of ENB and SMAA injector and started again, utilising the proxy dll feature in the ENB config and it's all fine. Skyrim looks great! Getting some stuttering when I look at certain places so I think I was a bit ambitious with the texture sizes on 1GB VRAM, I'll have to look into sorting that with DDSopt or something. Thanks again!