Starfield is based on the Creation Engine 2, a technical legacy that opens the door to modifications from day one, but also imposes specific constraints. The release of the official Creation Kit by Bethesda in June 2024 has restructured the scene: two modding circuits now coexist, with different rules and limits depending on the platform.
SFSE and Creation Kit: two Starfield modding circuits to distinguish
The first circuit goes through Nexus Mods and often relies on SFSE (Starfield Script Extender). This tool extends the engine’s capabilities by directly accessing the game’s memory. Mods that depend on it can modify deep systems: interface, skills, NPC behavior.
The second circuit uses the Creations system integrated into the game. This is the only one accessible on Xbox, where players cannot install Nexus mods that require SFSE or native plugins. On PC, both circuits coexist, significantly expanding the possibilities.
This distinction has a direct impact on stability. An article referenced by several technical sources describes how Starfield modding on Vos Jeux addresses this coexistence between the two systems and the precautions to take before mixing mods from both sources.
Load order and conflicts between Starfield mods
The majority of crashes and bugs related to mods do not come from the number of modifications installed. Stability depends on dependencies and load order, not volume. Two plugins that modify the same data tables (inventory, skills, NPCs) can produce unpredictable behaviors, even on a lightweight installation.
Specifically, each mod that adds a .esm or .esp file inserts itself into a load order list that the engine reads sequentially. If two files modify the same record, the last one loaded overwrites the first. Without a mod manager, this hierarchy remains invisible.
Managing load order with a dedicated manager
Tools like Vortex (published by Nexus Mods) or Mod Organizer 2 allow you to visualize and reorder this list. They also report direct conflicts between files. A few points to systematically check:
- A mod that modifies the interface (like StarUI) should generally load after mods that add new objects, to keep the display consistent.
- Mods requiring SFSE must be associated with the correct version of the Address Library, or they risk crashing at launch.
- Any mod marked as dependent on another plugin must be placed after it in the load order.
Field reports vary on the usefulness of automatic sorting for Starfield, as sorting tools like LOOT do not yet have the same maturity of rules as for Skyrim or Fallout 4. Manual sorting often remains more reliable.
Starfield updates: why your mods may stop working
Each patch released by Bethesda can modify the memory addresses used by SFSE. When this happens, SFSE and all mods that depend on it become temporarily unusable. The Address Library, an intermediary file that links SFSE and the game, must be updated before relaunching anything.
In practice, this means that after a game update, launching Starfield with outdated SFSE mods can cause an immediate crash. The most direct precaution is to disable automatic updates on Steam and manually check compatibility before each update.
Backups and mod uninstallation
Problems can persist after uninstalling a mod. If a mod modifies save data (adding items, changing character stats), removing that mod does not clean the save. The game then attempts to load references that no longer exist, which can corrupt the save.
Two practices reduce this risk:
- Create a manual backup before each addition or removal of a mod, and keep it separately.
- Never remove a mod mid-game without checking its Nexus page to see if it is marked as “safe to remove.”
- Test new mods on a secondary save before applying them to a main save.
StarfieldCustom.ini file and mod folder structure
Most guides mention the StarfieldCustom.ini file without explaining its exact role. This file, placed in the Documents/My Games/Starfield folder, allows the game to load mod archives (.ba2) that are not natively referenced.
The key line to add in the [Archive] section is bInvalidateOlderFiles=1, along with sResourceDataDirsFinal pointing to the folder containing the loose files. Without this configuration, the game simply ignores the mod files copied into the installation directory.
To locate the installation folder on Steam: right-click on Starfield in the library, then Manage, then Browse local files. The Data folder at the root is where most mods should be extracted.
Manual installation or via manager
Manual installation (extracting an archive into the Data folder) works for simple mods. However, a mod manager becomes necessary as soon as the installation exceeds five modifications, as it allows you to disable a mod without deleting its files and quickly restore the original state.
The PC Game Pass version of Starfield complicates things: the installation folder is protected by Windows permissions, making manual installation more cumbersome. The Steam version remains the easiest to mod.
Starfield modding continues to evolve as the Creation Kit and community tools gain maturity. Before installing anything, checking compatibility with the current version of the game and the potential presence of SFSE dependencies remains the most useful precaution, the one that avoids most common problems.
