If you find a legitimate message in your spam folder, you can unblock it to ensure that you continue to receive similar messages in the future. Like blocking, unblocking is reported to the Cloudmark network, where it is used to correctly identify legitimate messages in the future, for all users in the network.
DesktopOne asks you whether you want to add the sender of this message to your Approved Senders list. See Using the Approved Senders list.