stride3d/stride · error · InvalidOperationException

Could not find a valid content serializer for

Error message

Could not find a valid content serializer for {typeof(T)} when loading {contentReference.Location}

What it means

ReferenceSerializer<T>.Serialize resolves a content serializer for T when serializing a content reference. If neither the cached serializer nor the one derived from the stored chunk header type can be resolved, the library cannot construct or serialize the referenced content and throws.

Solutions

  1. Ensure the assembly containing the referenced content type is loaded (AssemblyRegistry) before deserialization
  2. Register a serializer for the concrete content type of the asset
  3. Rebuild/re-save the asset so its chunk header matches a currently registered type
  4. Verify the contentReference.Location points to the intended asset of a serializable type

Example fix

// before
// plugin assembly with MyAssetType never loaded
var asset = contentManager.Load<MyAssetType>("my-asset"); // throws
// after
AssemblyRegistry.Register(typeof(MyAssetType).Assembly);
var asset = contentManager.Load<MyAssetType>("my-asset");
Defensive patterns

Strategy: try-catch

Validate before calling

if (AssemblyRegistry.GetType(chunkType) == null)
    throw new InvalidOperationException("Assembly for asset type not loaded");

Try / catch

try { var asset = contentManager.Load<T>(location); }
catch (InvalidOperationException ex) when (ex.Message.Contains("valid content serializer")) { // ensure assembly/serializer registered
}

Prevention

When it happens

Trigger: Serializing/deserializing a content reference whose Location points to content of a type with no registered serializer, or whose chunk header type fails AssemblyRegistry.GetType resolution (assembly not loaded or removed).

Common situations: Loading assets built with types from an assembly no longer referenced; a plugin/asset type removed in a version upgrade; corrupt or hand-edited asset files with unknown chunk types.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

AI-assisted analysis of stride3d/stride@96fad776d2 (2026-09-14). Data as JSON: /api/errors/eb563365dcec02a0. Report an issue: GitHub.

Appendix: source

Thrown at sources/core/Stride.Core.Serialization/Serialization/Contents/ReferenceSerializer.cs:61

                    // Check if already deserialized
                    var assetReference = contentSerializerContext.ContentManager.FindDeserializedObject(contentReference.Location, typeof(T));
                    if (assetReference != null)
                    {
                        obj = (T)assetReference.Object;
                        if (obj != null)
                            contentReference.Value = obj;
                    }
                }

                if (obj == null && contentSerializerContext.LoadContentReferences)
                {
                    var contentSerializer = cachedContentSerializer ??= contentSerializerContext.ContentManager.Serializer.GetSerializer(null, typeof(T));
                    if (contentSerializer == null)
                    {
                        // Need to read chunk header to know actual type (note that we can't cache it in cachedContentSerializer as it depends on content)
                        var chunkHeader = contentSerializerContext.ContentManager.ReadChunkHeader(contentReference.Location);
                        if (chunkHeader == null || (contentSerializer = contentSerializerContext.ContentManager.Serializer.GetSerializer(AssemblyRegistry.GetType(chunkHeader.Type), typeof(T))) == null)
                            throw new InvalidOperationException($"Could not find a valid content serializer for {typeof(T)} when loading {contentReference.Location}");
                    }

                    // First time, let's create it
                    if (contentSerializerContext.ContentManager.Exists(contentReference.Location))
                    {
                        obj = (T)contentSerializer.Construct(contentSerializerContext);
                        contentSerializerContext.ContentManager.RegisterDeserializedObject(contentReference.Location, obj);
                        contentReference.Value = obj;
                    }
                }
            }
        }
        else if (referenceSerialization == ContentSerializerContext.AttachedReferenceSerialization.AsNull)
        {
            if (mode == ArchiveMode.Deserialize)
            {
                obj = default;
            }

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