How to Investigate A memory leak in a GameMaker Game

Investigating a memory leak in a GameMaker game is a discipline: gather evidence, form a hypothesis, confirm it, and fix the cause — in that order. The temptation is to skip to changing code, but without evidence every change is a guess that adds noise. The method is always the same: watch the heap over a long session, find the type that keeps growing, and trace where it's retained. This guide walks through investigating a memory leak in a GameMaker game, including the cases that only happen on machines you don't own.

A structured investigation in GameMaker

The reliable way to investigate a memory leak in a GameMaker game is to watch the heap over a long session, find the type that keeps growing, and trace where it's retained. Notice that this is a sequence, not a single leap: each step produces evidence that the next one builds on, so you converge on the cause instead of thrashing. The most common mistake is to start with the fix — changing things on a hunch — which usually buries the real cause under new variables.

Work from what the evidence actually shows. A memory leak in GameMaker is rarely as mysterious as it first feels once you are reading the trace, the heap, the profile, or the breadcrumbs rather than guessing at them.

Turning a pile of crashes into a ranked worklist

Raw crash data is overwhelming if every occurrence is its own line. The trick is grouping: identical failures, fingerprinted by their stack trace, collapse into one issue with a count. Suddenly the question “what should I fix first?” answers itself, because the bug hitting the most players sits at the top with the biggest number next to it.

That ordering is what makes a small team effective. You are never going to fix everything, but you do not have to. Fixing the top few signatures usually removes the large majority of real-world failures, and prioritising by frequency means your limited hours always go to the bug that matters most right now.

Connecting failures to the build that caused them

Regressions are the cruelest class of bug because they punish your most engaged players — the ones who already own the game and updated to your newest patch. A change meant to improve things quietly breaks something else, and without build-level tracking you have no way to link the dip in retention to the release that caused it.

The fix is to attach a build identifier to every captured failure. Then a new signature that appears the day you ship a patch is unmistakable, and you can roll back or hotfix while only a few players are affected instead of discovering the problem weeks later in your reviews.

The silent majority who never report anything

For every player who files a report, a large number simply hit the problem, sigh, and close the game. They do not owe you a bug report, and most will not write one. The failures that churn the most players are therefore the ones least likely to ever reach your inbox, which is a deeply unfair feedback loop: the worse the bug, the quieter it tends to be.

The only way out of that loop is to stop depending on goodwill. When every crash is recorded automatically, the silent majority become data. You finally see the failure that is quietly costing you installs, ranked by how often it actually happens rather than by who happened to be patient enough to complain.

Investigating a memory leak you can't reproduce

The hardest investigation is the one where a memory leak never happens on your machine, because it depends on hardware, timing, or a sequence you do not run. You cannot investigate what you cannot observe — at least not locally.

Automatic capture supplies the evidence remotely. The failure or the relevant data arrives from the player's device with the stack trace, the device and OS, the build, and the breadcrumb trail, so a memory leak you could never reproduce becomes a case you can actually investigate. Group identical occurrences to find the shared cause, fix the root, tie failures to builds, and confirm it's resolved in the next release.

This is where a tool like Bugnet earns its place. Its SDK captures every failure automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds identical failures into one grouped issue with an occurrence count, and ties each to the build it happened on. The result is that the abstract idea above stops being theory and becomes a ranked list you work down — the worst problem first, verified fixed when its signature disappears from the next release.

You cannot fix what you cannot see. Once the failure is in front of you with real context, the hard part is usually already over.