How to Delete Unopened Sent Mail in Microsoft Outlook
Emails that are written too quickly sometimes contain mistakes. Perhaps you have written an email containing a typo, or you sent it to the incorrect recipient. If your business uses an Exchange server for email, you may be able to recall your message in Microsoft Outlook before it is read by the recipient. Recall a message in Outlook to have Outlook attempt to delete an unopened mail before it is read.
Click on the "Sent Items" folder in Outlook.
Right-click on the mail that you want to delete, and click "Recall This Message." A new window opens.
Click the radio button labeled "Delete unread copies of this message."
Put a check in the box labeled "Tell me if recall succeeds or fails for each recipient" to have Outlook send you a message letting you know whether the recall operation was successful.
Click "OK." The email is deleted if the recipient has not opened or moved it.