unity serialization_error ai_generated true

The serialized field layout has changed. Serialization layout for type 'PlayerData' has been changed.

ID: unity/serialization-layout-mismatch

Also available as: JSON · Markdown
85%Fix Rate
88%Confidence
3Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
2022 active — — —

Root Cause

Serialized class layout changed between builds. Saved data (ScriptableObjects, prefabs, scenes) contain stale field definitions.

generic

Workarounds

  1. 92% success Use FormerlySerializedAs attribute when renaming fields 
    [FormerlySerializedAs("oldFieldName")] public int newFieldName;  // preserves serialized data

    Sources: https://docs.unity3d.com/Manual/upm-ui.html

  2. 85% success Implement ISerializationCallbackReceiver for complex migrations 
    OnAfterDeserialize() to convert old data layout to new format on load
  3. 82% success Re-serialize affected assets after changing fields 
    Select affected prefabs/ScriptableObjects > right-click > Reimport; or use ForceReserializeAssets API

Dead Ends

Common approaches that don't work:

  1. Delete all serialized data files and start fresh 85% fail

    Destroys save data and scene references. Use FormerlySerializedAs to migrate instead.

  2. Revert the class changes to match old serialization 72% fail

    Blocks progress. The correct approach is to migrate the data forward, not lock the code.