How to fix it?

Had this error myself and seen where plenty of others have. If you have any script based mods this error can occur, and two ways to possibly fix it. One is to download the Unification Patch off Nexus Mods and follow those steps and hopefully that will work. If not, second is to remove all or certain script based mods that aren't compatible with the update, though I found a list of them online, removing the incompatible ones did no good. Only thing that got the game to launch was removing all my mods. However for me, the game just crashes after trying to load a save file and get into gameplay. So broken for me pretty much atm, might just roll back the update.