In Outlook 2010, go to Files > Options > Mail and look under “Outlook panes” to find the Reading Pane button. In Outlook 2007, go to Tools > Options > Other and click Reading Pane to access these same options.

Just type in a value for “Wait n seconds before marking item as read.” This is great if you want to feel like you’ve just buzzed in on Jeopardy every time a message is read (“You have 15 seconds, sir…”). Or, if you want, you can go back to File > Options > Advanced and select the Mark items as read when viewed in the Reading Pane check box and change how long Outlook gives you before marking it as read. To mark it as unread again, press CTRL + U (this won’t unsend the read receipt, though).

When you’re ready to mark it as read, you can double-click it to open it or right-click and choose “Mark as read,” or press CTRL + Q (my fave). When you go back to Outlook, you can read the message in the Reading Pane with impunity. Mark item as read when selection changes.Mark items as read when viewed in the Reading Pane.

Under “Outlook panes,” click Reading Pane. You can read emails in the Outlook Preview Pane without marking them as read.

Microsoft outlook read receipt