If you recovered the VOCALOID computer system by restoring data using a backup tool, hard disk clone, or the like, the VOCALOID authorizer will not recognize the copied data.
In this case, please uninstall all VOCALOID components and re-install them. Once you have re-installed all components, please authorize them.

Uninstalling VOCALOID on a Windows computer:
Click [Start] > [Settings] > [Apps] > [Apps & features] and uninstall the VOCALOID software.

If uninstallation fails, install the software by overwriting the existing software.