When creating an application-aware backup, you need to specify a guest OS user from Administrators group.
If the guest OS user that you specify is not built-in Administrator, then the following changes must be applied in the guest OS so that this user can be used for application protection in Acronis Backup.
Otherwise, you will see one of these errors:
The specified user does not have enough rights to create an application-aware backup. User Account Control is enabled in the guest system and this user is not a built-in administrator.