OLEXP: Mail in Outbox Sent When You Send a New Message

If you click Send in a New Message window to send a new message, the message is sent using your default mail account. However, other messages placed in your Outbox using the Send Later Using command may also be sent on the specified accounts.

To prevent messages placed in the Outbox using the Send Later Using command and an account other than your default account from being sent when you click Send in a New Message window, move the messages from the Outbox before you send the new message.