How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix GameMaker Reading the Wrong Controller After Reconnecting

Q: What causes GameMaker reading the wrong controller after reconnecting?

You hardcode device 0 for input, but when a controller disconnects and reconnects it can be assigned a different slot, so your reads point at an empty or wrong device.

Quick answer: Listen to the Async System event for gamepad connect/disconnect, store the active device slot, and read input from that variable rather than a fixed 0.

If unplugging and replugging a pad makes input go dead or come from the wrong controller, you are locked to a fixed slot. Tracking the live slot fixes it. Here is how.

How to fix it

1. Handle the Async System event

In the Async > System event check async_load[? "event_type"] for "gamepad discovered" and "gamepad lost", and update a stored device variable accordingly.

2. Read from the stored slot

Replace every gamepad_button_check(0, ...) with your tracked player_pad variable so reconnects on a new slot keep working.

3. Re-apply per-device settings

After a reconnect re-run deadzone and axis setup for the new slot, since those settings are bound to the device index and reset on the new connection.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every GameMaker error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

Most of the time the fix is small. Seeing the failure clearly is the part that actually costs you.