Event Registrations are marked as incomplete as soon as the user clicks 'continue' to go to the payment page, this essentially holds their spot until the payment can be confirmed or rejected. If you are seeing an incomplete, it is likely that the final confirmation for that payment did not make it back to our system. For all gateways, other than DiamondMind, we have a process to resolve these incompletes as a success or failure. For DiamondMind, an incomplete should be deleted or confirmed to be processed(in which case, you should just leave the registries). An incomplete should appear for no longer than 30 minutes to an hour.