Machine Party second controller not joining

Identify what “second controller not working” means

Watch the lobby while only the second person presses a button. Does a new player appear, does an existing player react, or does nothing happen? Those observations point to different checks. A pad that moves an existing selection may be delivering input without owning a separate player seat.

Also distinguish input failure from a crash. If the application exits when a device is unplugged, record that event rather than calling it a missing second player. If both players have joined and only one action fails in a particular trial, read that trial’s live prompt before rebuilding the whole controller setup.

The same comparison works for a third or fourth missing controller. Keep the intended group within the documented player limit.

Make sure the extra pad joins through Local

Use the Local menu and reach its lobby before asking the additional controller to join. Attaching another pad to a PC in an online room is not the documented couch-play flow.

Connect the controllers before launch, then press a button on each pad separately in the Local lobby. Count the resulting players and complete any visible name and cosmetic steps before readying. If you have not hosted locally before, use the local co-op setup guide as the starting point.

One keyboard-and-mouse player can be part of the group. For a mixed pair, the keyboard and controller guide keeps that setup separate from a two-pad test.

Run the A/B controller test

1. Close Machine Party. Label the working controller A and the missing controller B so the results stay clear.
2. Disconnect A. Check B in Steam Settings → Controller and run its input test. If B is not detected there, try another cable, port, or connection before changing the game.
3. Launch the game with B alone and check whether it can join a Local lobby. Record the result, then close the game.
4. Connect both controllers, relaunch, and try joining B before A. Note whether the failure follows B or whichever device joins second.
5. Repeat only the comparison needed to isolate the failure. Keep the mode and other settings unchanged.

If B fails alone, focus on B’s detection and layout. If both work alone but not together, focus on device duplication, mapping software, or a repeatable multi-controller issue. If changing the join order changes the result, include that detail in a bug report without assuming player order is the permanent fix.

Remove extra mapping layers for one test

Close nonessential controller mappers and disconnect unused wheels, adapters, and virtual gamepads. Start with Steam’s default per-game controller setting. Relaunch after changing it so you can compare like-for-like results.

A community layout that sends keyboard keys can blur the difference between a pad and the keyboard seat. Try a standard gamepad layout while diagnosing the lobby. Change one mapping setting at a time, and restore an earlier setting if the change makes no difference.

If pressing one pad creates two players or moves multiple selections, follow the double-input guide. If Steam cannot detect the pad in the first place, the general controller-not-working guide covers that earlier stage.

If joining or reconnecting crashes the game

Update before repeatedly testing disconnects. The official v2.1.1 notes report a fix for a potential controller-disconnect crash in the local lobby. That is a specific historical fix, not confirmation that every controller problem was solved.

For a current failure, record whether it happens while adding a player, removing a pad, reconnecting Bluetooth, or readying up. Include the exact Local mode and whether it also happens with a wired connection. Avoid unplugging devices in the middle of a longer session just to reproduce a known setup problem.

When the second pad still will not join

Report the smallest repeatable case: controller A alone works, controller B alone works, but B fails when A is already joined, for example. Include the OS, game version, pad models, connection types, Steam Input override, and whether a separate mapping tool was running.

Use the pinned bug-report discussion from the game’s Steam discussions. Describe the expected extra player seat and the actual response. A clear two-device comparison is more useful than a list of every setting you tried.

Should I reinstall the game first?

Run the individual Steam input tests and a fresh Local lobby first. Reinstalling cannot show whether the second pad is detected by Steam or being exposed twice.

Can I keep using the keyboard instead?

One keyboard-and-mouse seat is a documented local option. It can help a group play while you investigate a specific pad, provided every intended player still has a separate seat.