It took me some time to find out (searching on Google would’ve been much faster!), but here’s how to view message headers of an email in Outlook 2007.
- Open a message (double click)
- In the Ribbon, locate Options (Follow-Up and Mark As Unread are buttons). In the Options area, click the small arrow in the right bottom.
This is called the Dialog Box Launcher
- The Message Options dialog box pops up. The headers appear in the Internet headers box