1.6.640 — Skyrim Update

Within 48 hours of release, every SKSE plugin broke. Here is the technical reason:

If you have already been updated and your mod list is broken, do this: skyrim update 1.6.640

Open your Data/SKSE/Plugins folder. Delete every .dll file. Then, reinstall them one by one, making sure the Nexus page lists 1.6.640 or AE (latest) in the requirements. Within 48 hours of release, every SKSE plugin broke

This is the part that technical players care about most. Update 1.6.640 wasn't just a content patch; it was an engine port. The Address Library for SKSE Plugins (by meh321)

The Address Library for SKSE Plugins (by meh321) had to be entirely regenerated. Plugin authors waited for:

Lesson: Do not update your game mid-playthrough unless you are willing to wait 1–2 months for all plugins to update.