A pet peeve of many users of Outlook is the fact that deleted messages that were unread when being deleted are counted in Deleted Items. Like the behavior when going from one unread email to another in the Reading Pane, there is a setting for this. Here’s how to change the behavior:
- Go to File -> Options
- Go to Mail
- Scroll down to Other
- Check the setting “Mark messages as read when deleted”:
As with other settings that do not involve account settings, the change should take effect as soon as you click OK to exit the dialog box.