From now on, do not launch Skyrim through Steam. You must run skse64_loader.exe to start the game with mod support. Why version 1.6.640 is a "Golden Build"
If you see an error saying you are running game version 1.6.1170 but need 1.6.640, Steam likely auto-updated your game. You will either need to download the latest SKSE version (3.0.x+) or use the Skyrim Special Edition Downgrade Patcher on Nexus Mods to go back to 1.6.640.
Essential mods like SSE Engine Fixes , Address Library , and Dynamic Animation Replacer work perfectly on this build. skse 16640 link
SKSE requires Steam to be active in the background. Even though you aren't clicking "Play" in Steam, the app must be open. Essential Next Steps
By staying on 1.6.640 with the corresponding SKSE link, you ensure: From now on, do not launch Skyrim through Steam
Once you have SKSE 1.6.640 running, your next priority should be installing the . Most modern mods use this to ensure they work across different versions of the script extender.
Open the SKSE archive. Copy every file inside the folder (especially skse64_1_6_640.dll , skse64_loader.exe , and skse64_steam_loader.dll ) and paste them directly into your Skyrim Special Edition folder. You will either need to download the latest SKSE version (3
This is usually found at: C:\Program Files (x86)\Steam\steamapps\common\Skyrim Special Edition (Tip: You can right-click Skyrim in Steam > Manage > Browse local files).