What does Windows error code 1712 (RPC_S_TYPE_ALREADY_REGISTERED) mean?

RPC_S_TYPE_ALREADY_REGISTERED

Manager type UUIDs select interface implementations

RPC_S_TYPE_ALREADY_REGISTERED concerns interface registration with multiple manager entry-point vectors. A server can expose one interface UUID while registering different manager implementations under different type UUIDs. Object UUID mappings then identify the type whose manager EPV should service the call.

The status indicates that the relevant type UUID is already registered for that interface. Registering the same type again is not a way to replace a manager implementation in place.

What to check

• Compare the interface specification handle and manager type UUID passed to each RpcServerRegisterIf* call.
• Look for duplicate initialization in plugins, service reload paths, or static constructors.
• If a server intentionally supports several implementations, assign distinct type UUIDs and map object UUIDs to the correct types.

Also distinguish this from an object UUID already being registered. The type registration belongs to the interface manager table; object registration belongs to the object-to-type mapping.

References

• Microsoft: Registering Interfaces
• Microsoft: RpcObjectSetType
• The Open Group: RPC object model