Fix: Addressables Catalog Update Failing in Unity

You’ve shipped a content update, pushed new bundles to your CDN, and triggered a build. But when players launch the game, Addressables.UpdateCatalogs() silently returns nothing — or worse, throws a cryptic RemoteProviderException. The old content persists. Your hotfix is stuck in limbo. This is one of the most frustrating Addressables issues because it fails quietly, and the logs rarely tell you the real story.

Understanding the Catalog Update Flow

Before diving into fixes, it helps to understand what actually happens when Addressables checks for a catalog update. The system performs a two-step verification process that’s easy to break if you don’t account for both parts.

When you call Addressables.CheckForCatalogUpdates(), the runtime downloads the remote .hash file and compares it to the locally cached hash. If they differ, the catalog is considered stale and UpdateCatalogs() will download the new catalog.json file. If the hashes match — even if the actual catalog content has changed — no update occurs. This is the root cause of most failures: the hash comparison is the gatekeeper, and if it’s wrong, everything downstream breaks.

The remote catalog consists of two files that must stay in sync: catalog_YYYY.MM.DD.HH.MM.SS.hash and catalog_YYYY.MM.DD.HH.MM.SS.json. If your CDN serves a cached version of one but the fresh version of the other, the update will either be skipped or fail with a hash verification error.

Fix 1: CDN Caching Headers on Hash Files

The most common cause of catalog update failures is CDN caching. Your CDN is doing exactly what it’s designed to do — serving cached content — but for hash files, this behavior is destructive. When a player’s client downloads a stale .hash file, it compares the old hash to its local cache, finds a match, and skips the update entirely.

Set explicit no-cache headers on your .hash files. In CloudFront, create a behavior pattern for *.hash with a custom cache policy:

// CloudFront cache policy for .hash files
{
  "MinTTL": 0,
  "MaxTTL": 0,
  "DefaultTTL": 0,
  "HeadersConfig": {
    "HeaderBehavior": "none"
  }
}

If you’re using Cloudflare, add a Page Rule for *yourdomain.com/*.hash with Cache Level: Bypass. For S3 directly, set the Cache-Control metadata on uploaded hash files:

aws s3 cp catalog.hash s3://my-bucket/catalogs/catalog.hash \
  --cache-control "no-cache, no-store, must-revalidate" \
  --content-type "text/plain"

The .json catalog file can be cached more aggressively since the hash file controls whether it gets downloaded. But if you want to be safe during rollouts, give it a short TTL of 60 seconds or less until you’ve confirmed the update is propagating.

Fix 2: Remote Catalog Configuration Errors

The second most common issue is an incorrect RemoteLoadPath. Open Window > Asset Management > Addressables > Profiles and check your RemoteLoadPath variable. It must exactly match the URL structure where your catalog files are hosted, including the trailing path separator.

A common mistake is using a build-time path variable that doesn’t resolve correctly at runtime. For example:

// Wrong - build path variable won't resolve at runtime
RemoteLoadPath: [BuildTarget]/[AppVersion]

// Correct - explicit URL with runtime variables
RemoteLoadPath: https://cdn.yourgame.com/addressables/[BuildTarget]

Also verify that Build Remote Catalog is enabled in your Addressable Asset Settings inspector. This setting controls whether the build process generates the remote catalog files at all. If it’s disabled, you’re only building local catalogs and no remote update can ever occur.

Check the Player Version Override field as well. If this is set, it replaces the timestamp in catalog filenames. If two builds produce the same player version override, the hash file name won’t change and clients may use a locally cached version without checking the remote.

Fix 3: Handling the Update in Code

Even with correct configuration, you can still hit issues if your update code doesn’t handle edge cases. Here’s a robust pattern for checking and applying catalog updates:

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

public async void CheckAndUpdateCatalogs()
{
    // Step 1: Check for updates
    var checkHandle = Addressables.CheckForCatalogUpdates(false);
    await checkHandle.Task;

    if (checkHandle.Status != AsyncOperationStatus.Succeeded)
    {
        Debug.LogError($"Catalog check failed: {checkHandle.OperationException}");
        Addressables.Release(checkHandle);
        return;
    }

    List<string> catalogsToUpdate = checkHandle.Result;
    Addressables.Release(checkHandle);

    if (catalogsToUpdate == null || catalogsToUpdate.Count == 0)
    {
        Debug.Log("No catalog updates available.");
        return;
    }

    // Step 2: Apply updates
    var updateHandle = Addressables.UpdateCatalogs(catalogsToUpdate, false);
    await updateHandle.Task;

    if (updateHandle.Status == AsyncOperationStatus.Succeeded)
    {
        Debug.Log($"Updated {catalogsToUpdate.Count} catalog(s).");
    }
    else
    {
        Debug.LogError($"Catalog update failed: {updateHandle.OperationException}");
    }

    Addressables.Release(updateHandle);
}

The false parameter in CheckForCatalogUpdates(false) prevents auto-releasing the handle, which lets you inspect the result before releasing manually. Pass the explicit list of catalog IDs to UpdateCatalogs() rather than passing null, which updates all catalogs — this gives you control over partial updates if you have multiple remote catalogs.

Debugging Catalog Issues with Addressables Profiler

When your catalog update fails silently, Unity’s built-in Addressables tooling can help you trace what’s happening. Enable verbose logging by setting the log level in your Addressable Asset Settings to Full under Catalog > Log Runtime Exceptions.

Open Window > Asset Management > Addressables > Event Viewer during a play mode session. This shows you every operation the Addressables system performs, including catalog requests, hash comparisons, and download attempts. Look for operations that start but never complete — these indicate network-level issues or timeout problems.

You can also add a global exception handler to catch provider errors that might otherwise be swallowed:

Addressables.ResourceManager.ExceptionHandler = (handle, exception) =>
{
    Debug.LogError($"Addressables exception on {handle.DebugName}: {exception}");
};

If you’re seeing InvalidKeyException after a catalog update, it means assets referenced in your code no longer exist in the updated catalog. This usually happens when you rename or remove Addressable groups between builds without updating all references. Track these errors with a bug reporting tool like Bugnet to catch them from player devices before they become widespread.

CDN caching is the silent killer of every Addressables pipeline. Fix the headers first, ask questions later.