SKSE (Skyrim Script Extender) is a tool used by many of the most complex Skyrim mods to expand the game’s scripting capabilities. Without it, mods like SkyUI , RaceMenu , and XP32 Maximum Skeleton simply won't function.
Go to the archived SKSE builds or the Nexus Mods page. You are looking for skse64_2_01_02.7z . skse 16342
While players often call it "SKSE 1.6.342" based on the game's version, the actual SKSE file version is 2.1.2 . Why This Specific Version is Important SKSE (Skyrim Script Extender) is a tool used
Right-click SkyrimSE.exe in your game folder, select Properties > Details , and ensure the "Product version" says 1.6.342 . mods like SkyUI