Co-op multiplayer for X4: Foundations — up to 4 players
Build 17 • 157 KB • Windows only
Right-click x4mp-build17.zip and choose Extract All. You will get a folder called x4mp.
Press Win + R, paste this and hit Enter:
%USERPROFILE%\Documents\Egosoft\X4
Open the folder with your Steam ID (a long number), then open extensions. If extensions doesn’t exist, create it.
Move the x4mp folder you extracted into extensions. The result should be:
...\extensions\x4mp\content.xml
Launch X4 → press Esc → Settings → General → find Protected UI Mode and set it to Off. Restart the game.
Once in-game (in your save), press Esc → Options → X4MP: Multiplayer to open the lobby panel.
To host: select Host, enter your name and a port (default 7842), click Start. Share your IP and port with friends.
To join: select Join, enter your name, the host’s IP, and the port, then click Start.
Protected UI Mode must be OFF or the mod will fail to load silently. If the X4MP entry is missing from the Options menu, go back to Step 4 and check.