How to Fix SerializedProperty Array Edits Not Saving in a Unity Editor Script

You change array elements with InsertArrayElementAtIndex or set values on a SerializedProperty, but after recompile or selection change the array is back to its old contents. The edits never reached the asset.

How to fix it

1. Apply after editing

Call serializedObject.Update() before reading and serializedObject.ApplyModifiedProperties() after writing. Without the apply, the SerializedObject's pending changes are thrown away.

2. Resize through arraySize

Grow or shrink arrays with prop.arraySize = n or InsertArrayElementAtIndex, then write each element. Editing the target's C# list directly bypasses the serialization layer Unity tracks.

3. Record undo for clean dirtying

Use ApplyModifiedProperties (which records undo and marks dirty) rather than setting fields and calling EditorUtility.SetDirty manually, which can miss array-size 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.