Magic effects and spell engine fixes - F4SE (updated)

F4SE plugin, fixes some engine bugs affecting NPC spells, inventory item enhancements, and Perks.

Original address:

Prefix:

Fallout 4 Script Extender (F4SE)：

Updated on August 20, 2026:

Version 3.2

Added support for game version 1.11.240.

Version 3.1

Hotfix for a bug in v3.0 that may cause game version 1.11.221 to be unrepairable after an NPC's 3D loading event.

Version 3.0

Added support for game version 1.11.221.

Version 2.1

Hotfix for "Allocation error, error code: 2".

Version 2.0

Added support for game version 1.11.191.

This module has been re-implemented in a new multi-version F4SE plug-in environment, without the need for an address library.

Fixed a bug in the AE (Anniversary Edition) version that could prevent effects from being reapplied after calling Disable() and then Enable() on an NPC. (This vulnerability only affects AE versions.)

Version 1.4

Added support for game version 1.11.169.

Version 1.3

Added support for game version 1.11.159.

Version 1.2

Added support for game version 1.11.137.

Version 1.1

Fixed a rare vulnerability that could cause Fallout4.exe+1D706C7 (non-next generation) or Fallout4.exe+175AE9D (next generation) to crash.

About this mod:

F4SE plugin, which fixes some engine bugs affecting NPC spells, inventory item enhancements, and Perks ("effects").

1) Fixed a bug that prevented certain effects from being re-applied to NPCs under the following circumstances:

• Equip items in the container menu ("Trade Menu")
• Call Disable() on them
• Their parent cells are unloaded (i.e. they are away from the player)
• Fast travel to distant places with them (relevant to companions only)

2) Fixed a bug that could randomly cause the same effect (e.g. +2 Wisdom ("Skill Spell")) to be applied to an NPC multiple times by the same source inventory item The plugin comes with a custom magic effects manager that requests vanilla code to re-evaluate these effects on save game load and periodically (for example, this should be part of vanilla's background process that does this for invisibility effects).

Here is a general article about these effects, and the "NPCs lose their magic effects" bug (source: fadingsignal).

Another article also describes how power armor breaks the rules of the game when it loses its effectiveness (Source: PJMail).

Notice:

• Other than fixing these issues, this addon does not change the vanilla behavior of spells, perks, or magic effects

• I (original author LarannKiar, the same below) made a mod that only patched the container menu code a few days ago; I decided to merge it into this one (no longer available)

• The plugin fixes bug codes for all NPCs, not just companions

• Multi-threading of the plugin: although the Magic Effect Manager is lightweight, it runs in another thread like any background process - Manager and ContainerMenu patches can be turned off completely in the INI (for mod vs. vanilla comparison)

• Plugin does not make NPCs persistent

• Thanks to Sranger for alerting me to this issue

compatibility:

Should be compatible with anything.

I made two versions; for the non-next-gen and next-gen version of the game (both address-agnostic).

Prerequisites:

Fallout 4 Script Extender (F4SE) (download the file corresponding to the game version):

Address Library for F4SE Plugins (download the file corresponding to the game version):

The packaged standard version (supports version 1.10.163) and the next-generation version (supports version 1.10.984, with the word Next-Gen) are uploaded together. You can choose one of the two to install according to your needs.