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Navigating Skyrim Special Edition 1.6.640: The Ultimate SKSE Guide (2021-2022 Updates)

For users running Skyrim v1.6.640, the specific compatible version of the Skyrim Script Extender (SKSE64) skyrim+skse+16640+2021

Because you will always launch the game via skse64_loader.exe (and through your mod manager), Steam will never register that the game was launched, effectively halting the update indefinitely. Verifying the Installation Navigating Skyrim Special Edition 1