diff --git a/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetEntity.cs b/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetEntity.cs
index e0b2bce574..dc34a1b0de 100644
--- a/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetEntity.cs
+++ b/backend/src/Squidex.Domain.Apps.Entities.MongoDb/Assets/MongoAssetEntity.cs
@@ -73,7 +73,7 @@ public static void RegisterClassMap()
 
             cm.MapProperty(x => x.TotalSize)
                 .SetElementName("ts")
-                .SetIsRequired(true);
+                .SetIsRequired(false);
 
             cm.MapProperty(x => x.Type)
                 .SetElementName("at")