Avamar Server 7
A scheduled backup or a backup initiated from the Policy window for the MC_SYSTEM account fails immediately with a status of "No Data".
Note that the Client is listed as the Avamar Grid name and the Domain is /MC_SYSTEM.
If the Client is not <AvamarGridName> and the Domain is not /MC_SYSTEM, please see KB: Backup fails with "No Data" status (Resolution Path) , for more scenarios where this error can occur.
Hovering over the status reveals that the "Activity Failed - client has no data specified by dataset"
To prevent this error, either disable the Default Group (preferred) and create distinct groups for actual clients, or create a new group for MC_SYSTEM and disable this new group.