Lethal Company mods come from Thunderstore and run on BepInEx. The easiest way is r2modman (or the Thunderstore Mod Manager), which installs BepInEx and every dependency for you, and lets you share a profile code so your whole lobby has the same mods.
Steps
- Install r2modman. Download it from its Thunderstore page and pick Lethal Company.
- Create a profile. Keep a separate profile per modpack so you can switch easily.
- Install BepInExPack. r2modman adds it automatically with your first mod.
- Install mods. Search the Online tab. r2modman pulls in required libraries such as LethalLib and InputUtils.
- Start modded. Launch the game with the Start modded button, not from Steam.
- Share the profile. Use Settings › Profile › Export profile as code, and have friends import it. Everyone needs the same gameplay mods.
- Test in a solo lobby first. Make sure the game reaches the ship without errors before inviting friends.
Common pitfalls
- Mismatched mods in a lobby. Different mod lists or versions cause desyncs or failed joins. Share one profile code.
- Outdated mods after a game update. Big updates (v50, v60, v70...) break many mods. Check update dates on Thunderstore and ModSafe's status.
- Launching from Steam. That starts the vanilla game. Use the manager's Start modded button.
- Too many content mods. Mods that add many moons or monsters can clash. Add a few at a time.
Rolling back
- Disable or uninstall a mod in r2modman, or switch back to another profile.
- Start vanilla from Steam to play without mods.
- r2modman can install an older version of a mod (Online tab › mod › select version) if a new one breaks.