Quick answer: Unity AssetPostprocessor calling AssetDatabase methods during OnPostprocessAllAssets causing editor deadlock? Postprocessors must defer cross-asset operations - schedule via EditorApplication.delayCall.

Postprocessor that imports auxiliary files crashes the editor mid-import.

Defer the operation

EditorApplication.delayCall += () => {
  AssetDatabase.ImportAsset(path);
};

Runs after the import pipeline completes. No deadlock.

Or use deferred queue

Postprocessor appends to a static List; an EditorWindow processes the list on update. More structured.

Avoid reentrant imports

Postprocessor must not trigger imports that re-trigger itself. Audit for cycles.

“Asset Database is reentrant-hostile. Postprocessors need to know.”

Document the postprocessor pattern in your tools wiki. New contributors will write recursive imports otherwise.