steam_api.dll and rename it to steam_api.dll.bak or move it to a backup folder. Do not delete it; you need it if you want to play on Steam again.steam_api.dll and steam_interfaces.txt into the Bin folder (or the root folder if the fix specifically instructs so).When Serious Sam 3 launched, Croteam used Steamworks for its multiplayer backend. Normally, even "LAN" games send a handshake to Steam's servers. If Steam is offline, or you aren’t logged in, the multiplayer button grays out. The goal is to decouple the game from Steam's DRM and redirect its network discovery to pure IPX/ UDP broadcast.
Open Command Prompt as Admin. Find your LAN IP (ipconfig). Then launch the game via shortcut with these parameters:
Create a new shortcut to Sam3.exe. Right-click → Properties → Target. Append: how to play serious sam 3 multiplayer lan without steam
+net_startserver +map Single_Level01_Intro +game_mode 2 +maxplayers 8 +port 25600
You will need two specific files generally found in "Serious Sam 3 LAN Fix" packs:
Note: Serious Sam 3 is generally a 32-bit application, so the steam_api.dll is usually the target file. Backup Original Files: Locate the original steam_api
If players cannot see each other, the issue is almost always Windows Firewall.
Disable Firewall Temporarily:
Network Profile:
Direct Connect:
Want to receive push notifications for all major on-site activities?