A:The MAC address of the on-board LAN is erased. After updating the BIOS or clearing the CMOS, please boot up the system and enter the BIOS setup. After loading the BIOS default, please exit and save changes. Failing to do so may cause the MAC address disappeared. If the MAC address is gone, please contact ASRock technical support engineer for help. ( https://www.asrock.com/general/about.asp?cat=Contact )