How to View the Complete Email Message Source in Outlook
►https://www.lifewire.com/view-complete-message-source-outlook-1173713
C’est compliqué ... il vaut mieux utiliser un client mail qui respecte le format et enrégistre le contenu d’un mail « comme il est ».
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.