The Backup Exec admin group contains the name of the users who have permission to back up and restore the Macintosh systems.
When you install the Remote Agent for Macintosh Systems, Backup Exec creates the admin group and adds root as a member. Any Macintosh user that you add to the admin group gets the necessary permission to back up and restore the Macintosh systems.
However, if an NIS server is detected during the Remote Agent installation, Backup Exec cannot create the admin group. After the installation, you must create the admin group manually on the Macintosh system. You must create the admin group before you start backup and restore operations. Otherwise, connections fail between the Macintosh system and the media server.
Before the members of the admin group can perform backup or restore operations, they must have a Backup Exec logon account.
More Information
Creating the Backup Exec admin group manually on Macintosh systems