A "normal" email client stores messages as it receives them — with all the header lines and the body, separated by a blank line. With its Exchange background and a complicated local storage system, Outlook does this a bit differently.
Outlook Takes Internet Emails Apart
Outlook takes messages it receives from the internet apart as soon as it sees them. It stores the headers independently from the message body and breaks out the individual message parts, too. When it needs a message, Outlook collects the pieces to show just what is needed. You can have it display all the headers, for example.
Unfortunately, the original message structure is lost, though. Even when you save the message to disk as an .msg file, Outlook only saves a slightly modified version (the Received: header lines are stripped, for example).
Fortunately, you can tell Outlook to preserve the complete source of internet messages, though. How Outlook operates will not change, but you can retrieve the original source of messages as they were received at any time.
Make Available the Complete Message Source in Outlook
To set up Outlook so you can see the complete source of emails:
- Press Windows-R
- Type "regedit".
- Hit Enter.
- For Outlook 2013:
- Go to HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Options\Mail.
- For Outlook 2010:
- Go to HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Options\Mail.
- For Outlook 2007:
- Go to HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Options\Mail.
- For Outlook 2003
- Go to HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Options\Mail.
- Select Edit | New | DWord from the menu.
- Type "SaveAllMIMENotJustHeaders".
- Hit Enter.
- Double-click the newly created SaveAllMIMENotJustHeaders value.
- Type "1".
- Click OK.
- Close the registry editor.
- Restart Outlook if it has been running.
See the Complete Source of a Message in Outlook
Now you can retrieve the source of newly retrieved POP messages (editing the SaveAllMIMENotJustHeaders value does not restore the complete message source for emails that were already in Outlook):
- Open the desired message in its own window.
- Double-click the email.
- Click FILE.
- Make sure the Info category is open.
- Now click Properties.
- Find the source to the email under Internet headers:.
- Click Close.
See the Complete Source of a Message in Outlook 2003/7
To open a message's full source in Outlook 2003 and Outlook 2007:
- Click on the desired message with the right mouse button in the Outlook mailbox.
- Select Options... from the menu.
- Find the message source under the (now improperly named) Internet headers: section.
(Updated March 2014)