Stopping the Memory Leak: Transitioning to Unity Addressables for Dynamic Asset Loading

The Problem with Direct References

In a standard Unity project, dragging a prefab into a serialized field in the Inspector creates a hard reference. While convenient, this means that if a scene references a large character model, that model—and every texture, material, and audio clip attached to it—is loaded into RAM the moment the scene initializes. As projects grow, this leads to bloated memory footprints, long loading screens, and out-of-memory crashes on mobile devices.

The useful takeaway is that Unity's Addressables Asset System lets you request assets by key at runtime instead of bundling them into every scene that might need them. This decouples asset references from physical file paths and shifts loading to an asynchronous model.

Decoupling Assets from Scene Logic

Addressables replace traditional Resources folder paths and direct Inspector references with a system of keys. An address is typically a string (for example, "PlayerCharacter") or a GUID. At runtime, Unity consults an Addressable Content Catalog to resolve that key to a physical location, whether the location is inside the local build or on a remote server.

This shift enables asynchronous loading. Because the system resolves the key through the catalog rather than a direct reference, it can fetch data in the background. That prevents the main thread from freezing, reducing the frame hitching common when instantiating complex objects during gameplay.

Worked Example: Loading a Prefab in a Coroutine

Before writing code, install the Addressables package through Unity's Package Manager, then mark an asset as Addressable in the Inspector. The Addressables window (Window → Asset Management → Addressables) shows the generated catalog and lets you confirm the package is present.

The following script loads a prefab by key inside a coroutine. Attach it to a GameObject in a scene where the asset key Enemy_Orc has been marked as Addressable. The handle is stored so the asset can be released when the object is destroyed.

using System.Collections;
using UnityEngine;
using UnityEngine.AddressableAssets;
using UnityEngine.ResourceManagement.AsyncOperations;

public class AddressableLoader : MonoBehaviour
{
    [SerializeField] private string assetKey = "Enemy_Orc";
    private AsyncOperationHandle<GameObject> _handle;

    private IEnumerator Start()
    {
        _handle = Addressables.LoadAssetAsync<GameObject>(assetKey);
        yield return _handle;

        if (_handle.Status == AsyncOperationStatus.Succeeded)
        {
            Instantiate(_handle.Result, Vector3.zero, Quaternion.identity);
        }
        else
        {
            Debug.LogError($"Failed to load asset with key: {assetKey}");
        }
    }

    private void OnDestroy()
    {
        Addressables.Release(_handle);
    }
}

Where to run it: This code runs inside the Unity runtime, not the Editor. The primary risk is a memory leak. Unlike standard objects, assets loaded via Addressables must be explicitly released. If you load an asset repeatedly and never call Addressables.Release, the memory will not be reclaimed even if the instantiated object is destroyed.

The Trade-off: Build Complexity vs. Runtime Flexibility

Addressables provide power, but they introduce build management overhead. You can no longer simply press Build and Run. You must build the Addressable Content Catalog before the application can resolve keys, and you must manage catalog versioning to avoid stale references when content changes remotely.

The initial catalog also adds a small load-time overhead before any addressable asset can be retrieved. Misconfigured bundle settings can increase final build size, so compression options and dependency grouping require deliberate choices. For very small projects, this overhead may not be justified; for projects with large asset libraries targeting mobile or consoles, the on-demand model is usually worth the complexity.

Verifying the Result

To confirm the workflow works, build the catalog from the Addressables window and run the scene. Then open the Unity Profiler and compare memory consumption and load times against a traditional synchronous load. Look for the async operation completing without a long main-thread stall, and verify that memory drops after Release is called. If the Profiler shows memory remaining allocated after the object is destroyed, the handle was not released correctly.

A practical next step is to convert one frequently used prefab to an addressable, measure the difference in your own project, and expand from there once the release pattern is comfortable.