Nucleus Co-op Controllers: Setup and Input Fixes

Start with a simple Nucleus Co-op controller test

The fastest way to diagnose Nucleus Co-op controllers is to remove variables. Close virtual controller software, unplug devices you are not testing, and begin with one game handler that already launches normally. Connect the input devices before starting the instances, then give each device a clear identity such as Controller 1 or Controller 2.

Test movement and menu navigation one player at a time. If Controller 1 moves both windows, stop before changing resolution or graphics settings. Shared input usually points to device exposure, input API behavior, focus, or handler configuration. A clean test tells you whether the problem belongs to Windows, the game, the handler, or the Nucleus Co-op input layer.

Understand XInput, DirectInput, and handler expectations

Windows can expose controllers through different input APIs. Many PC games behave most predictably with XInput devices, while other controllers or adapters may appear through DirectInput. Nucleus Co-op and a game handler may expect one API, translate another API, or require a separate tool. The controller name printed on the shell is therefore not enough evidence that the game will receive the same device in the same way.

Use the controller type that the handler documents first. If a PS4, PS5, or Joy-Con controller is visible in Windows but does not respond in the game, check whether the game expects XInput and whether the handler has a specific mapping note. Do not install several translation layers at once: each one can change the device order and make a previously clear input problem harder to reproduce.

Fix one controller controlling both Nucleus Co-op instances

When one controller controls both instances, first check whether the game receives a global device instead of an isolated device. Pause the session, close extra virtual controllers, disconnect unused gamepads, and test again with one physical controller at a time. If the behavior changes after a controller tool is enabled, the tool or its device order is part of the diagnosis.

Also check window focus and the handler notes. Some games poll every connected controller globally, while others bind input to the active window or a translated device. Nucleus Co-op can help with supported input paths, but it cannot force every game to expose independent controller slots. Keep the exact game, handler, controller type, and input tool version in your notes.

• Close DS4Windows, reWASD, Steam Input, vJoy, HidHide, and similar tools for the baseline test unless the handler requires one.
• Disconnect unused controllers and Bluetooth devices that Windows may still enumerate.
• Test the same controller outside Nucleus Co-op so you know how the game normally assigns it.
• Check whether the handler requires XInput, DirectInput, or a virtual-device setup.
• If only the focused window responds, test borderless/windowed mode and the handler's input notes.
• Record the result after each change instead of changing the controller, handler, and game settings together.

Use keyboard and mouse with split-screen instances

Keyboard and mouse input is often more focus-sensitive than controller input. A game may accept keyboard events only from the active window, while the mouse can be captured, clipped, or reported relative to a different window size. Start with one keyboard and one controller, then test a second keyboard path only when the handler and game explicitly support it.

If the mouse appears in the wrong place, first use the handler's default window size and a normal monitor scale. Check Windows display scaling, borderless mode, overlays, and which instance owns focus. Resolution and ultrawide fixes belong after input routing works; otherwise a display change can hide the original problem.

PS4, PS5, Joy-Con, and mixed controller setup

PS4, PS5, and Joy-Con setups can work in some Nucleus Co-op games, but the result depends on how Windows exposes the device and what the game handler expects. A controller that works in one title can fail in another because the game uses a different API, player-slot rule, or launcher path. Treat the working game and handler combination as the scope of your test rather than a universal controller guarantee.

For a mixed setup, assign one device family first. For example, verify two XInput controllers, then add the PS5 controller or Joy-Con pair and observe whether the device order changes. If a handler update breaks a previously working input arrangement, compare the old and new handler notes and keep the exact error or input symptom.

• Pair or connect the devices before launching the Nucleus Co-op session.
• Check the Windows game-controller panel and confirm every physical device is visible once.
• Avoid duplicate virtual representations of the same PS4 or PS5 controller.
• Use the game handler's notes for controller translation or required input tools.
• Test a simple two-device arrangement before adding keyboard, mouse, Joy-Con, or virtual inputs.

Final Nucleus Co-op controller checklist

Before a long session, confirm the game launches normally outside Nucleus Co-op, the handler matches the exact edition, and each controller or keyboard path responds independently. Save a short note with the application version, handler version, game build, input devices, and working window mode. That record is more useful than a generic claim that controllers worked once.

If the controller problem remains, use the troubleshooting hub and include the complete symptom: whether the game opens, which instance receives input, whether the issue happens with one controller, and whether a translation or virtual-device tool is active. Clear evidence helps separate an input assignment problem from a game or handler compatibility limit.

• The game opens normally outside Nucleus Co-op.
• The handler and game edition match.
• Each device appears once in Windows.
• Player one does not move player two's instance.
• Keyboard focus and mouse capture are predictable.
• The connection method required by the game has been tested separately.

Nucleus Co-op controller FAQ