[Description] This value is of type REG_DWORD, and is used by the event log service to determine whether an event log should be automatically saved. The default value is 0, which disables auto-backup. The service will back up the log file only if the retention value is -1 (0xFFFFFFFF). Other values will be ignored. Windows Server 2003: Retention can be set to -1 (0xFFFFFFFF) or 1 (0x00000001) for AutoBackupLogFiles to work. Other values will be ignored. [Registry value] 
AutoBackupLogFiles