Fallout 4 Script Extender (F4SE)
fallout-4 — Mods & Enhancements
F4SE is a plugin that extends the game's scripting engine, allowing mods to call native functions that Bethesda never exposed to Papyrus. It enables complex features like custom UI, real-time inventory manipulation, and advanced physics hooks, all without modifying the game's executable. Players install it as a mandatory dependency for hundreds of mods, including 'Sim Settlements', 'Place Everywhere', and 'LooksMenu', because it unlocks the ability to create dynamic scripts that run faster and more reliably than vanilla Papyrus.
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Downloads: 7,954,080 | Endorsements: 97,421💡 Notes
By F4SE Team | v0.7.8 | 97,421 endorsements
🎯 Tips & Tricks
Do not use Vortex's 'Mod Manager Download' for F4SE. Instead, download the '7z archive' from the F4SE website, extract it, and copy the 'f4se_1_10_163.dll', 'f4se_1_10_163.ini', and 'f4se_loader.exe' files directly into your Fallout 4 root folder (where Fallout4.exe is). Then run 'f4se_loader.exe' as administrator to launch the game with F4SE active.
F4SE is version-specific. Check your game's version by right-clicking Fallout4.exe > Properties > Details. If you have the latest Steam version (1.10.163), use F4SE build 0.6.23. If you have an older version (e.g., 1.9.4), download the corresponding F4SE from the 'Archive' section. Mismatched versions cause immediate crash on launch.
Once F4SE is running, open the console with ~ and type 'getf4seversion' to confirm it's loaded. For mods that use F4SE, type 'sqv <modname>' to see if their quests are running. This helps troubleshoot 'LooksMenu' or 'MCM' not appearing in the pause menu.
🔧 Troubleshooting
F4SE crashes with 'Fallout 4 - High Resolution Texture Pack' DLC
The DLC adds a large BA2 file that F4SE sometimes fails to index. In the F4SE.ini file (in the same folder as f4se_loader.exe), add [Loader] bLoadArchive=0 to disable archive pre-loading. This forces F4SE to load archives dynamically, fixing the crash at the startup logo.
Incompatibility with 'Ultimate Window Overhaul' mod
This mod uses F4SE's 'GetInventoryItem' function which was changed in F4SE 0.6.20. Update F4SE to the latest build, then in the mod's MCM, set 'Use Legacy Inventory' to 'Yes'. This reverts to the older script call and prevents a CTD when opening workshop mode near windows.
⚠️ Common Mistakes
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👍 Pros
- 97,421 endorsements
- 7,954,080 downloads
- Category: Utilities
👎 Cons
- Requires mod manager installation
- May conflict with similar mods