How to save a mail into an .eml-file with Outlook?

Seems like Outlook is lacking this feature. You can save the message as MSG and then convert it to EML. This can be done with the free developer tool called MFCMapi.

1. Save the message to Outlook Message Format (MSG) via File → Save As…
2. Download MFCMapi,
   • make sure you use version of MFCMapi matching your OL version (x64 for x64 outlook, x86 for x86 outlook).
3. Start it, go to Advanced → Import/Export → Convert MSG to EML.
4. Leave all the fields to default, press OK and choose the MSG file.
5. Save the EML file to the desired location.

None of the solutions worked with Outlook 2016, but there is a workaround using the OWA Webmail interface:

1. Open the OWA Webmail view to your list of emails
2. Click the "New" -> "Email message" button.
3. Drag the mail you want to export as .eml into the new email body from the sidebar. It will show up as an attachment.
4. Click the little arrow on the attachment, then "Download" in the menu (see screenshot).
5. You'll get a .eml file called "eml" which will contain the full original email including all headers and attachments.

On older (yellow) versions of the OWA web interface Outlook, you can do the following instead:

1. Create a new email draft
2. Drag two (2) mails into the draft
3. Send the email to yourself
4. Open the email you just sent and click on the "Download all attachments" button.

I often need to do this task, so I wrote an online utility to do that.

There are similar tools out there, but they are mostly full of ads and ask you to register first. There are just two steps in mine:

1. Upload an .msg
2. Download an .eml

Hope it'll be useful for someone.

I happen to have stumbled across this utility that might be a nice free add-on for Outlook http://www.outlookfreeware.com/en/products/all/OutlookMessagesExportEML/

Hope this helps. It really would've been nice if Outlook included this ability and maybe even the ability to export to "mbox" format so we can port it to a Unix mail system.