🎮 Game Error Codes What it means & how to fix it

Lethal Company Won't Let You Join? Here's the Fix

Nearly every Lethal Company 'can't join lobby' problem in 2026 is one of two things: a mod-list mismatch (the host runs mods you don't, or a different version), or a Steam lobby/region hiccup. Fastest fix: if either player uses mods, BOTH must run the exact same mods and versions (use a mod manager profile and share it). For vanilla, set the lobby to Public or Invite-Only and use a direct Steam invite instead of the public browser.

Lethal Company multiplayer — how sessions actually connect

Networking model
Steam P2P (Steam relay) — no port forwarding needed; a stuck lobby is a Steam relay/region issue, not your router
Save file path
C:\Users\<you>\AppData\LocalLow\ZeekerssRBLX\Lethal Company
Save gotcha
Only the HOST saves. Non-host players keep no progress. No Steam Cloud — saves are local only, autosave only when the ship enters orbit
Common cause of 'can't join'
Host on a modded/BepInEx build with a version mismatch — all players must run the exact same mod set

Last verified: September 2026

Error codes

Lobby not showing / no lobbies found The public browser returns nothing or omits the host's lobby

Cause: Lobby set to Invite-Only/Friends, a region filter, or the browser being flaky.

Fix:
  1. Host: set lobby visibility to Public (or Invite-Only and send a direct Steam invite).
  2. Both players set the same region if the mod/menu exposes one.
  3. Skip the browser — accept a Steam invite from the host's friend list.
  4. Restart Steam if the friends list shows the host offline in-game.
Connection to host was lost / kicked on join You connect briefly then drop, or get booted immediately

Cause: Mod-list or game-version mismatch between host and client.

Fix:
  1. Both players must run the EXACT same mods at the same versions (share a mod-manager profile code).
  2. Confirm you're on the same game build (a Steam update on one side breaks joins).
  3. Disable BepInEx mods entirely on both sides to test if a mod is the cause.
  4. Verify game files on both PCs, then re-launch through the same mod manager.

Fixes that work for most Lethal errors

  1. If modded: BOTH players run identical mods and versions — share a mod-manager (r2modman/Thunderstore) profile.
  2. If vanilla: both on the same game build; a one-sided Steam update blocks joining.
  3. Use a direct Steam invite instead of the public lobby browser.
  4. Set lobby visibility to Public or Invite-Only (Friends-only can hide it).
  5. Restart Steam if the host appears offline in your friends list in-game.
  6. Verify game files: Steam > right-click Lethal Company > Properties > Installed Files > Verify integrity.
  7. Test vanilla (mods off on both sides) to isolate whether a mod is the cause.

FAQ

Why can't I join my friend's Lethal Company lobby?

The most common cause is a mod mismatch: if either of you runs mods, both must run the exact same mods and versions. Share a mod-manager profile so they match, or both play fully vanilla.

Why does it say 'connection to host was lost'?

That usually means a mod-list or game-version mismatch, or the host's lobby dropped you. Confirm identical mods and the same game build on both PCs, then rejoin via a direct Steam invite.

Why are no lobbies showing in the browser?

The public browser is unreliable and hides Invite-Only/Friends lobbies. Have the host set the lobby to Public or, better, send you a direct Steam invite from their friends list.

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