If you receive 0x80073BC3, 0x8007002, 0x80073B92 - 0x20009 error code during Windows Update, its because of multiple system partitions which confuses the update process. The full error message

The requested system device cannot be found, there is a sharing violation, or there are multiple devices matching the identification criteria.

If you have installed a new system drive but left the previous system drive connected, it causes the conflict. The only way to resolve this is remove/disconnect that contains the unused system partition. You can also choose to disable the drive from the BIOS.

Once the upgrade is complete, reconnect the drive or Enable it. The next obvious step is to delete the unused system partition.