Some murmuring on UDN as of a year ago suggests that creating UObjects from worker threads (and not just the async loading thread) is now supported. The Async object flag will be set automatically, and should be manually unset once the object’s referenced from the root set (or once you’ve kept it from being GCable through some other means). Notably, it’s NOT okay for the worker thread to put a reference to that object in a main-thread-accessible object, as the GC might be running and get confused by it.