BepInEx Setup for Casualties Unknown
Most mod problems start before the first mod is installed. This page is the loader checklist: where the files go, how to prove the loader ran, and how to unwind a bad install.
Quick answer
- Install the loader into the game folder, not into a random subfolder.
- Launch the game once and confirm the loader log exists before adding any mod.
- A mod that does not appear in the log is not loading, regardless of where you copied it.
- Keep a clean backup so an uninstall is a folder swap, not a reinstall.
What BepInEx does
BepInEx is a mod loader. It starts before the game's own code, discovers plugin files, and gives those plugins a place to hook into the game. If the loader does not start, no plugin mod will work, even if the files are in the right place.
The loader writes a log. That log is the single most useful diagnostic you have. Learn where it lives before you install anything.
Install steps
- Close the game and the launcher. A running process locks files and produces half-copied installs.
- Back up the game folder. A zip of the clean folder is enough.
- Download the loader from its official release page. Match the architecture the game uses.
- Extract into the game folder. The loader files should sit next to the game executable, not inside a nested duplicate folder.
- Launch the game once. Close it after the main menu appears.
- Confirm the log file exists. If it does not, the loader did not run.
Game/BepInEx/BepInEx/.What the folder layout should look like
| Path | Purpose |
|---|---|
Game/ | Contains the game executable |
Game/BepInEx/core/ | Loader core files |
Game/BepInEx/plugins/ | Plugin mods |
Game/BepInEx/config/ | Generated configuration files |
Game/BepInEx/LogOutput.log | Loader log written at startup |
If your layout differs, stop and compare it to the loader's own documentation. Guessing at the structure is how people end up with two loaders installed at once.
Verify the loader before adding mods
Open the log and search for the loader version line and the plugin scan section. A healthy first run shows the loader starting, scanning the plugins folder and finishing without a fatal error. At this stage the plugin list may be empty; that is expected.
If the game launches but no log appears, the loader never injected. Recheck the install path, the architecture and whether another loader is already present.
Troubleshooting ladder
- Game will not launch at all: remove the plugins folder and test the loader alone.
- Game launches but no mods: confirm the plugin file is in
plugins/and appears in the log. - One mod fails: remove only that mod and relaunch. Read its log line.
- Everything fails after an update: the loader or mods are behind the game build. Roll back or wait.
- Still stuck: restore the clean backup and start again from step one.
Do not stack fixes. Change one thing, launch, and read the log.
Clean uninstall
Delete the loader folder, then restore any files the install replaced from your backup. Launch the game unmodded to confirm it still works. If you skip that check, you will not know whether a later problem comes from the game or from leftover loader files.
Run this checklist
0 / 6 doneFrequently asked questions
Where do BepInEx plugins go?
In the loader's plugins folder inside the game directory. The plugin file must appear in the loader log at startup.
The game launches but no mods load. What now?
Check that the plugin is in the correct folder, that the loader log exists, and that the loader version matches the game build.
Do I need a new loader after a game update?
Sometimes. Check the loader release notes and the mod pages for the build they support before updating.
Can I install two loaders?
No. Two loaders in one game folder is a reliable way to break startup. Remove one completely before trying another.
How do I undo everything?
Delete the loader folder and restore the backed-up game files, then launch unmodded to confirm the baseline.
Add mods one at a time
A working loader is the foundation. Add a single mod, test it, then continue.