I haven't tried this yet but the members at Steam think it works. Most blame nVidia drivers and rolling back fixes it while others update to the new drivers and THAT fixes it. Who knows.
Here is the fix I found, change Ambient Occlusion to HBAO+:
"ionutpetre79

Aug 17 @ 1:24am


Originally posted by ➳Omega♎Tortilla♖:
Originally posted by ionutpetre79:
Yes. This Fixed the problem for me. Thanks !
How do you change it?
From game launcher under play, options -> look for advanced button and in the Fallout 4 Advanced Option window u should be able to set Ambient Occlusion to HBAO+ that is if ur video card supports that function. if not then u can either turn off Ambient Occlusion or install the old drivers."