I have come up with an Error on nexus mod manager that says game needs to be installed (all mods uninstalled). Which it was. I just run game through steam one time to setup the game ini files it is looking for... I just do sanctuary hills till I can exit at the character creation in the mirror (required only once to fix this warning). I use FO4SE (run as administrator).
I have also had a problem with fps after complete re-install of mods. Same fix except I only need to get to the splash screen (from steam start FO4) and options detect video settings. Exit and then restart FO4SE.
For those on PC, discovered just last night, playing with my NVidia card settings, several rendering settings, how many frames to pre-render, power management, etc... setting was let 3D application manage, or optimal power.
I nixed everything that let's the 3D application manage (FO4) and set for maximum in all cases, maximum performance, max pre-rendered, etc. The tab where the rotating NVidia symbol also needs to be changed from 3D application to maximum performance.
I tried it last night while trying out "50 ways to die"... cant wait to try SS tonight - went from a 20fps in the shop with the dancing ghoul girl, to a solid 60fps using fps limiter on ENB hotkey.
Hope this helps.
John