How to Fix Unity OnValidate Causing Errors or Slowdowns

OnValidate causing issues is doing unsafe work in it. Keeping it light fixes it. Here is how.

How to fix it

1. Keep it light and safe

OnValidate should only validate and clamp values, not do heavy work or have side effects. It runs on value changes and load in the editor, where instantiating or accessing the scene is not safe.

2. Do not instantiate or destroy

Creating or destroying objects in OnValidate is not allowed and causes errors, since it runs during serialization. If you need to react to changes by changing the scene, do it from a button or a deferred call, not OnValidate.

3. Defer heavy work

If a value change should trigger heavy work, mark it and do the work later (a deferred editor call, or at runtime), rather than in OnValidate. Heavy work in OnValidate slows the editor every time a value changes.

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.