Receiving, by a computer, a message from a sender to transmit to one or more recipients, comparing, by a computer, the message to a previous message transmitted to the one or more recipients, wherein the previous message is stored in a memory, determining, by the computer, that the message has a content similarity above a predetermined threshold to the previous message transmitted to one of the one or more recipients, providing, by the computer, the sender an option to prevent the message from being transmitted to one of the one or more recipients, and cancelling, by the computer, the message transmission, as a result of both the determination that the message has content similarity above the predetermined threshold, and as a result of the sender providing confirmation to prevent the message from being transmitted, and notifying, by the computer, the sender that the message transmission has been cancelled.