If you have lost the serial number, please contact the hardware manufacturer who provided you with the OEM version of Acronis True Image. During the upgrade process, you will be prompted to specify the serial number of your OEM version. If you have received Acronis True Image OEM with a serial number, you can upgrade to the full version of Acronis True Image regardless of whether Acronis True Image OEM is still installed on your PC. Upgrade from an OEM version with a serial number To be able to upgrade to Acronis True Image from an OEM version, you either need to have this OEM version installed and activated on the PC, or you need to have the serial number of the OEM version on hand.