If you've lost your serial number, please contact sales@marinersoftware.com to have your serial number sent via email to you. Please note that if you purchased a Mariner product from a reseller such as the Apple Store or Amazon, you will have need to register the serial number included in the retail box on our web site . If you did not register on our registration page on our web site,  for lack of a better way of explaining this, we have no way of knowing what serial number you purchased from any given retailer.