Why does my game work in the editor but not in the build?

Because the editor and build are different environments, and the game is relying on something true in the editor but not the build: assets present in the editor but not packaged, editor-only code or file paths, code that's stripped/optimized differently in the build (exposing latent bugs), or timing/performance differences. The build only has what was packaged and runs differently than the editor.

Why does my code behave differently in the build than the editor?

Because the build strips and optimizes code that the editor doesn't, debug checks and assertions are removed, code is optimized (which can expose latent bugs like uninitialized variables or undefined behavior), and editor-only code paths aren't present. Code that relied on debug/editor behavior, or had latent bugs the editor tolerated, behaves differently in the build. Fix the underlying bug rather than relying on editor behavior.

How do I avoid 'works in editor, breaks in build' problems?

Test the actual build regularly, not just the editor, since the build is what ships and these bugs by definition don't appear in the editor. Ensure all assets are packaged, don't rely on editor-only code or paths, fix latent bugs the optimized build exposes, and handle timing differences. Make build testing a habit so editor-versus-build discrepancies are caught during development rather than by players.

How to Fix a Game That Works in the Editor but Not in the Build

Quick answer: When a game works in the editor but breaks in the build, the cause is one of the differences between editor and build: assets present in the editor but not packaged into the build, code or file paths that work only in the editor, code that's stripped or optimized differently in the build, or timing/performance differences. Always test the actual build, identify what differs from the editor, and make the game rely only on what's true in the build, not editor-only behavior.

"Works in the editor but not in the build" is one of the most common and confusing problems in game development, the game runs perfectly while you're developing, then breaks once built. The editor and the build are different environments, and the game is relying on something that's true in the editor but not the build. Fixing it means finding that difference and not depending on editor-only behavior.

Why the Editor and Build Differ

The editor is a development environment with conveniences and behaviors the build doesn't have, so relying on editor-only behavior breaks in the build. Common differences: assets not included, the editor can access all your project assets, but the build only has what was packaged, so a missing-from-build asset works in the editor and fails in the build. Editor-only code/paths, code that runs only in the editor, or file paths that work in the editor's project structure but not the build's, behave differently. Stripped/optimized code, the build strips and optimizes code (debug checks removed, code optimized), so code relying on debug/editor behavior or with latent bugs can behave differently (see release-only crash fixes). And timing/performance differences, the build runs at different speed/timing than the editor, exposing timing-dependent bugs.

The throughline: the game assumes something the editor provides that the build doesn't. The build is the real target, so anything that only works in the editor is a bug waiting to surface.

How to Diagnose It

Test the build, not the editor, this is the fundamental discipline, since the build is what ships. When something works in the editor but not the build, identify what differs: is an asset missing from the build (check packaging)? Is editor-only code or an editor-specific path involved? Is it a stripped/optimized-code difference (a latent bug exposed, see release-build crash fixes)? Is it timing-dependent (works at editor timing, breaks at build timing)? The nature of the break narrows it.

Bugnet captures crashes and errors with context from the build, so build-only failures surface with traces and context that the editor wouldn't show, which is essential because these bugs by definition don't appear in the editor. Capturing what the build actually does in the field (or in build testing) reveals problems invisible during editor development, which is exactly the class of bug here.

How to Fix It

Make the game depend only on what's true in the build. For missing assets, ensure all needed assets are packaged into the build (the most common cause; verify asset inclusion). For editor-only code/paths, don't rely on editor-only behavior or editor-specific file paths, use build-valid paths and code that works in the build, and properly handle any editor-versus-runtime distinctions. For stripped/optimized-code issues, fix the latent bug the build exposes (initialize variables, eliminate undefined behavior, don't rely on debug-only behavior, see release-build fixes). For timing differences, fix timing-dependent bugs so the game is correct at build timing.

The overarching fix is to test and develop against the build's reality, not the editor's conveniences, and never assume editor behavior carries over. Make testing the actual build a regular habit (not just shipping the editor-tested version), so editor-versus-build discrepancies are caught during development rather than by players. A game that's built to rely only on what's true in the build won't suffer the 'works in editor, breaks in build' surprise.

Editor-only behavior breaks in the build because the game relies on something the editor provides and the build doesn't, assets, paths, debug code, or timing. Test the build, not the editor.