What you can back up with synthetic backup

Only file system resources are supported for synthetic backup.

Supported resources include common file system objects, such as volumes, drives, folders, and System State. Do not include database resources or other unique resources in the selection list.

Note:

Backup Exec only supports synthetic backups for System State in Windows 2000.

Backup Exec will not create synthetic backup jobs when the selection list that is associated with the synthetic backup policy contains unsupported resources.