How to Fix a GameMaker Persistent Controller Object Duplicated on Room Restart

A persistent controller survives room changes by design, but it is still re-created if you re-enter the room where it was placed. Without a guard, you end up with two global controllers.

How to fix it

1. Add a singleton guard in Create

In the controller's Create event, check instance_number(object_index) > 1 and call instance_destroy() on the extra so only the first survives.

2. Place it in the first room only

Add the controller instance to the very first room and let persistence carry it forward, instead of placing a copy in every room.

3. Reset state instead of recreating

When you intentionally restart, reset the persistent controller's globals rather than spawning a new instance, keeping the global controller singular.

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.