If the MS4640A Series VNA requires service or calibration, the system may be returned to factory specifications and re-imaged with a standard software configuration. User installed applications and data may be lost and unable to be retrieved. It is advised that user data be backed up, copied, and retained by the user. Applications will need to be reinstalled from their original installation disks. A complete system restore from a previous user backup is not advised after service or calibration as this will result in the new calibrations being overwritten, thus voiding the calibration accuracy.