From now on, always launch your game using skse64_loader.exe . ⚠️ Common Troubleshooting "SKSE Version Mismatch"
By staying on 1.6.640 and "locking" the version, you prevent Steam from automatically updating your game and breaking your entire mod list. Common Issues & Fixes skse 16640 link
Here is the official, safe, and direct information: From now on, always launch your game using skse64_loader
Finding the Right SKSE for Skyrim Version 1.6.640 Skyrim Special Edition (SSE) From now on
The correct version of for game version 1.6.640 is 2.2.3 .
Here’s how to find the correct file for game version 1.6.640 (the "16640 link"):