How to Fix IL2CPP Stripping a Reflection-Used Method in Unity

Your game runs in the editor but throws missing-method or null type errors after an IL2CPP build because the stripper removed code only your reflection paths touch. Telling the linker to preserve those types fixes it.

How to fix it

1. Add a link.xml

Create an Assets/link.xml listing the assembly and types to keep, e.g. <assembly fullname="MyGame" preserve="all"/>. Unity feeds this to the IL2CPP linker so the named code is never stripped.

2. Mark members with [Preserve]

Annotate individual classes, methods, or fields reached only by reflection with [Preserve] from UnityEngine.Scripting. This is more surgical than preserving a whole assembly and keeps build size down.

3. Lower the stripping level to confirm

Temporarily set Managed Stripping Level to Disabled in Player Settings and rebuild. If the bug vanishes, stripping is the cause, and you can re-enable it once your link.xml covers the missing types.

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.