Quick answer: Call steam_set_achievement or steam_set_stat_int, ensure stats are stored, and handle the Steam async event to confirm the store before relying on the unlock.

If a GameMaker game's Steam achievements never pop, the set call ran but the value was not committed or confirmed. GML batches stats and reports results through the async Steam event.

How to fix it

1. Set then commit

Call steam_set_achievement("ACH_ID") or steam_set_stat_int, and make sure the runtime stores stats so the change is uploaded rather than kept local.

2. Handle the async event

Process the Steam Async Event and read async_load to confirm the store succeeded. Treat a failure as a retry, not a silent success.

3. Check init succeeded

Confirm steam_initialised() returns true before any stat call. If Steam never initialized, every set silently no-ops.

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.