unity-addressables-design

Every LoadAssetAsync or InstantiateAsync call returns a handle that must be released via Addressables.Release or Addressables.ReleaseInstance. Forgetting to release keeps the AssetBundle in memory indefinitely, and using GameObject.Destroy on an InstantiateAsync instance does not decrement the refcount.

Addressables 2.9.1 removed all non-Async obsolete methods like LoadAsset and Instantiate, replaced IList<object> overloads with IEnumerable, and added SceneReleaseMode for scene unload control. LegacyResourcesLocator, DiagnosticEvent, and RegisterDiagnosticCallback were also removed.

Unity 6 ships Addressables 2.9.1, which removed all non-Async variants such as LoadAsset, Instantiate, LoadScene, and Initialize that were only marked Obsolete in 1.22.3. Replace every call with its Async counterpart and switch IList<object> key arguments to IEnumerable.

WaitForCompletion is unsupported on WebGL and throws because the JavaScript backend cannot synchronously pump async operations. Use await handle.Task or the Completed event instead, and guard any WaitForCompletion usage with platform conditionals.

Call CheckForCatalogUpdates first, then pass the returned stale catalog list to UpdateCatalogs, optionally with autoCleanBundleCache on 2.9.1. Skipping the check re-downloads every catalog each launch, and running updates with live handles can invalidate them.

AssetReference caches its OperationHandle, so a second LoadAssetAsync without releasing throws an active-handle InvalidOperationException. Either call ReleaseAsset between loads or use Addressables.LoadAssetAsync with ref.RuntimeKey for independent concurrent loads.