---
uid: addressables-api-initialize-async
---

# Addressables initialization

The Addressables system initializes itself at runtime the first time you load an Addressable or make another call to an Addressable API. Call [`Addressables.InitializeAsync`](xref:UnityEngine.AddressableAssets.Addressables.InitializeAsync*) to initialize Addressables earlier. This method does nothing if initialization has already happened. 

## Initialization tasks

The initialization operation performs the following tasks:

* Sets up the [`ResourceManager`](xref:UnityEngine.ResourceManagement.ResourceManager) and the [`ResourceLocators`](xref:UnityEngine.AddressableAssets.ResourceLocators).
* Loads configuration data that Addressables creates from StreamingAssets.
* Executes any [initialization object](xref:addressables-asset-settings) operations.
* Loads the content catalog. By default, Addressables first checks for updates to the content catalog and downloads a new catalog if available.

The following Addressables settings can change initialization behavior:

* [Only update catalogs manually](xref:addressables-asset-settings): Addressables won't automatically check for an updated catalog. Refer to [Updating catalogs](xref:addressables-api-load-content-catalog-async) for information about manually updating catalogs.
* [Build Remote Catalog](xref:addressables-asset-settings): Addressables won't try to load remote content without a remote catalog.
* [Custom certificate handler](xref:addressables-asset-settings): Identify a custom certificate handler if you need one to access a remote asset hosting service.
* [Initialization object list](xref:addressables-asset-settings): Add the [`IObjectInitializationDataProvider`](xref:UnityEngine.ResourceManagement.Util.IObjectInitializationDataProvider) ScriptableObject to your application that Addressables invokes during the initialization operation.

Set the following runtime properties before the initialization operation starts:

* [Custom URL transform function](xref:addressables-api-transform-internal-id).
* [ResourceManager exception handler](xref:UnityEngine.ResourceManagement.ResourceManager.ExceptionHandler).
* Static properties used for any custom runtime placeholders in  [Profile variables](xref:addressables-profile-variables). 

## Initialization objects

You can attach objects to the Addressable Assets settings and pass them to the initialization process at runtime. For example, you can create a [`CacheInitializationSettings`](xref:UnityEditor.AddressableAssets.Settings.CacheInitializationSettings) object to initialize Unity's [`Cache`](xref:UnityEngine.Cache) settings at runtime. 

To create your own types of initialization object, create a ScriptableObject that implements the [`IObjectInitializationDataProvider`](xref:UnityEngine.ResourceManagement.Util.IObjectInitializationDataProvider) interface. Use this object to create the [`ObjectInitializationData`](xref:UnityEngine.ResourceManagement.Util.ObjectInitializationData) asset that Addressables includes with your the runtime data.

### Cache initialization objects

Use a [`CacheInitializationSettings`](xref:UnityEditor.AddressableAssets.Settings.CacheInitializationSettings) object to initialize Unity's [`Cache`](xref:UnityEngine.Cache) settings at runtime.

To specify the cache initialization settings that the Addressables system uses:

1. Create a CacheInitializationSettings asset (menu: __Assets > Addressables > Initialization > Cache Initialization Settings__).
2. Select the new asset file in the Project panel to view the settings in the Inspector
   ![](images/cache-initialization-settings.png)

3. Adjust the settings as desired.
4. Open the Addressables Settings Inspector (menu: __Window > Asset Management > Addressables > Settings__).
5. In the __Initialization Objects__ section of the Inspector, click the __+__ button to add a new object to the list.
6. Select the CacheInitializationSettings asset in the File dialog and click __Open__.
7. The cache settings object is added to the list.

When Addressables initializes at runtime, it applies these settings to the default Unity `Cache`. The settings apply to all AssetBundles in the default cache, not just those downloaded by the Addressables system. Refer to [Caching](xref:UnityEngine.Caching) for more information about the Unity cache system.

> [!TIP]
> Android applications built with Unity 2020.1 or earlier, or running on Android 9 or earlier can only play videos from uncompressed AssetBundles. To disable recompression of the cache, use a `CacheInitializationSettings` object by disabling the __Compress Bundles__ option.