Save As / Export Email (msg file) in OWA

I just tried that, since I'm tired of my saved messages disappearing after 2 years.  Create a new message, drag and drop the message I want to save into the new message.  Right click on the newly created attachment, choose download.  This is the goofiest thing ever.  Why couldn't I just right click on the message in my inbox, and actually pick a folder to download to?

Alan_McFarlane 

Yes, a .MSG file is much more than an .EML one. In a short a MSG file is a Microsoft proprietary binary format dealing with MAPI objects then managed in Outlook while an EML file is encoded in a RFC text format human-readable. A standard .EML message transferred across the Internet becomes a proprietary MSG Outlook database item or standalone file when it reaches your local Outlook mailbox.

More details:

 - The .EML file format is a plaintext MIME (RFC 822) file format for storing emails, e.g. used by Microsoft Outlook Express, Windows Mail and Mozilla Thunderbird. Instead, .MSG is a compound file binary format based on Microsoft’s Outlook MAPI.

 - As part of the messaging workflow, the .MSG file is formatted by the MDA (Mail Delivery Agent) from the basis of the EML-structured message: when an email comes in your provider's messaging system, the distant MTA (Mail Transfer Agent) sends it to your provider's MDA that will break down the email in a lot of different MAPI objects before storing all of them in your local mail store. Your Microsoft Outlook acts as a MRA/MUA (Message Retrieval/User Agent) and it will pick up and store the retrieved messaging items (messages, meetings, and so on) in its proprietary PST/OST database in a proprietary MAPI format.

Pretty good information here to understand how a standard EML-formatted message becomes proprietary MSG-formatted message when handled by Microsoft Outlook :

https://stackoverflow.com/questions/16229591/difference-between-a-msg-file-and-a-eml-file

https://en.wikipedia.org/wiki/Email_agent_(infrastructure)