Unity-Technologies/UnityCsReference · warning · NotImplementedException

GlobalObjectIdentifierToInstanceIDSlow is obsolete. Use Glob

Error message

GlobalObjectIdentifierToInstanceIDSlow is obsolete. Use GlobalObjectIdentifierToEntityIdSlow instead.

What it means

GlobalObjectIdentifierToInstanceIDSlow(GlobalObjectId) is [Obsolete(..., true)] and throws NotImplementedException because the int-instance-ID return concept is being removed in favor of EntityId. The message directs callers to GlobalObjectIdentifierToEntityIdSlow, which returns the strongly-typed EntityId.

Source

Thrown at Editor/Mono/GlobalObjectId.bindings.cs:129

                TargetPrefab = targetPrefab
            };

            return true;
        }

        // Converting one object at a time is incredibly slow. (Have to iterate whole scene to grab one object...)
        // Always prefer using batch API when multiple objects need to be looked up.
        [FreeFunction]
        extern public static UnityEngine.Object GlobalObjectIdentifierToObjectSlow(GlobalObjectId id);
        [FreeFunction]
        extern public static void GlobalObjectIdentifiersToObjectsSlow(GlobalObjectId[] identifiers, [Out] UnityEngine.Object[] outputObjects);

        // Converting one object at a time is incredibly slow. (Have to iterate whole scene to grab one object...)
        // Always prefer using batch API when multiple objects need to be looked up.
        [Obsolete("GlobalObjectIdentifierToInstanceIDSlow is obsolete. Use GlobalObjectIdentifierToEntityIdSlow instead.", true)]
        public static int GlobalObjectIdentifierToInstanceIDSlow(GlobalObjectId id)
        {
            throw new System.NotImplementedException("GlobalObjectIdentifierToInstanceIDSlow is obsolete. Use GlobalObjectIdentifierToEntityIdSlow instead.");
        }
        [Obsolete("GlobalObjectIdentifiersToInstanceIDsSlow is obsolete. Use GlobalObjectIdentifiersToEntityIdsSlow instead.", true)]
        public static void GlobalObjectIdentifiersToInstanceIDsSlow(GlobalObjectId[] identifiers, [Out] int[] outputInstanceIDs)
        {
            throw new System.NotImplementedException("GlobalObjectIdentifiersToInstanceIDsSlow is obsolete. Use GlobalObjectIdentifiersToEntityIdsSlow instead.");
        }

        [FreeFunction]
        extern public static EntityId GlobalObjectIdentifierToEntityIdSlow(GlobalObjectId id);
        [FreeFunction]
        extern public static void GlobalObjectIdentifiersToEntityIdsSlow(GlobalObjectId[] identifiers, [Out] EntityId[] outputEntityIds);

    }
}

View on GitHub (pinned to 225b0fbdb5)

Solutions

1. Replace the call with GlobalObjectIdentifierToEntityIdSlow(id) and consume the EntityId.
2. If a raw int is unavoidable downstream, convert the EntityId explicitly at the boundary.
3. Migrate storage from int instance IDs to EntityId.

Example fix

// before
int instanceId = GlobalObjectId.GlobalObjectIdentifierToInstanceIDSlow(gid);

// after
EntityId entityId = GlobalObjectId.GlobalObjectIdentifierToEntityIdSlow(gid);

EntityId entityId = GlobalObjectId.GlobalObjectIdentifierToEntityIdSlow(id);

When it happens

Trigger: Calling the single-id reverse-lookup that returns an int instance ID; legacy code resolving a GlobalObjectId back to an instance ID; plugins not yet migrated.

Common situations: Cross-version Unity upgrade crossing the EntityId migration; copied legacy sample code; tooling that stored GlobalObjectIds and reverse-resolved to ints.

Related errors

• GlobalObjectId.GetGlobalObjectIdSlow(int[], [Out] GlobalObje
• GlobalObjectIdentifiersToInstanceIDsSlow is obsolete. Use Gl
• GetRenderersFilteringResults(ReadOnlySpan<int>) is obsolete.
• GetRenderersHiddenResultBits(ReadOnlySpan<int>) is obsolete.
• EditorApplication.OpenScene() cannot be called when in the U

AI-assisted analysis of Unity-Technologies/UnityCsReference@225b0fbdb5 (2026-08-13). Data as JSON: /api/errors/7be52c771a2cecf6. Report an issue: GitHub.