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 a Unity AssetPostprocessor Running on Every Asset Instead of Yours

Q: What causes a Unity AssetPostprocessor running on every asset instead of just yours?

AssetPostprocessor callbacks fire for every matching asset import in the project, so without a path or type guard your code rewrites import settings for files it should leave alone.

Quick answer: Guard the callback by checking assetPath against your intended folder and bail out early for anything outside it, and split texture, model, and audio logic into the type-specific OnPreprocess methods.

You wrote an OnPreprocessTexture to force settings on your UI sprites, but suddenly every texture in the project imports with those settings. Postprocessors are global by default.

How to fix it

1. Filter by asset path

At the top of the callback, check assetImporter.assetPath and return immediately if it is not under your target folder, so only intended assets are modified.

2. Use the right callback

Put texture rules in OnPreprocessTexture, model rules in OnPreprocessModel, and so on. Each fires only for its asset type, narrowing the blast radius.

3. Reorder with GetVersion and GetPostprocessOrder

If multiple postprocessors fight, set GetPostprocessOrder so yours runs predictably, and bump the version returned by GetVersion when you change logic so assets reimport once.

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 Unity 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.

A crash you can name from its stack trace is a crash you can usually fix in minutes.