If you are searching for 1.6.640 specifically , you are likely a modder who refuses to update to 1.6.1170 because a critical mod (like .NET Script Framework or NGIO) never got updated for the latest version.
Many essential mods require Address Library to function. Without it, you may see errors like:
In-game, open the console (press the tilde key ~ ) and type:
To get the exact match for your game, you must look into historical file repositories: 1. The Right Build Numbers
[Pre-2021 Era: v1.5.97] ──> [Nov 2021: Modern AE Era (v1.6.318)] ──> [Sept 2022: Safe Haven v1.6.640] ──> [Dec 2023+ Creations Updates] skyrim+skse+16640+2021
Then the Gray Man started appearing.
Whether you choose to stay on 1.6.640, downgrade to 1.5.97 using the "Best of Both Worlds" patcher, or move forward to newer runtimes, one truth remains: Without it, the game that has captivated millions for over a decade would be a fraction of what it is today. With it, the boundaries of Tamriel are limited only by the imagination of its community.
The 16640 Ghost
As stated in official sources, SKSE does not support the Windows Store, Game Pass, or Epic Games Store versions of Skyrim. Step-by-Step Installation Guide (1.6.640) If you are searching for 1
This is why you might want to stay on 1.5.97 (the "pre-AE" build). These mods were never updated past runtime 1.5.97 because their authors quit modding or the source code was lost.
Path example: C:\Program Files (x86)\Steam\steamapps\common\Skyrim Special Edition\
Tell you which are a "must-have" for this version.
For Skyrim SE version 1.6.640, you need . The Right Build Numbers [Pre-2021 Era: v1
If you are using the GOG version, always download the SKSE build labeled for GOG, not the Steam build.
Once in-game, open the system menu (press Esc ). If SKSE is installed correctly, you will see the SKSE version number (2.0.20) displayed in the bottom-left corner of the menu.
This refers to Skyrim Special Edition version 1.6.640 (released September 2021) paired with SKSE64 build 2.0.20 (or later matching builds from late 2021). This was the last stable pre-Anniversary Edition update before Bethesda pushed the AE “free upgrade” (1.6.318–1.6.640 range). Many modders still consider this build a sweet spot.
Scroll to the bottom. Look for any lines stating that a specific .dll plugin failed to load or is incompatible.