By default, Outlook marks items as read when viewed in the Reading Pane whenever the selection changes. You can turn this functionality off, or have Outlook wait a certain amount of time before marking the item as read. I use the latter method, setting Outlook to wait 60 seconds. That way, if I view a message that is going to take too long to read, I can move on to other messages without having the item marked as read. I will then go back to it later when I have more time to view it.
1. Open Outlook.
2. Go to the Menu bar, click Tools and select Options.
3. Select the Other tab.
4. Go to the Outlook Panes section and click the Reading Pane button.
5. If you wish to prevent Outlook from automatically marking items as read, uncheck the Mark item as read when selection changes checkbox.
To set Outlook to wait a certain amount of time before marking the item as read, check the Mark items as read when viewed in the Reading Pane checkbox and input the desired amount of seconds into the textbox. I use 60 seconds as the value I wish Outlook to use. This allows me to manage my time reading emails, letting me review emails and leave the longer ones for a later time.
6. Click the OK button.
