When it comes to OS specifically you actually have a few options when it comes to your unregistered sprite (besides registering it);
- You can thread the complex form Static Veil to prevent their OS from increasing each combat turn from maintaining illegal User or Admin access from Brute Forcing their way into a Host (but it will still gain OS from opposing hits).
- You can repeat thread the complex form Cleaner to reduce it's OS.
Having said that, your unregistered sprite is only used for a shorter period of time (typically only some hours). If you plan on using it for a longer period of time you have to register it. This will also reset its OS.
You can also spend one of it's tasks to re-register already registered sprite if you want to add more tasks to it (and/or if you wish to reset it's OS again).