Prevent backing up to network location This setting lets you prevent users from selecting a network location for storing backups. If this setting is enabled, users will be blocked from selecting a network location as a backup location. If this setting is disabled or not configured, users can select a network location as a backup location.

(1) GPO: Computer Configuration\Administrative Templates\Windows Components\Backup\Client!Prevent backing up to network location (2) REG: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Backup\Client!DisableBackupToNetwork