Email messages by default are saved in the Outlook MSG format, with a .msg extension, when saved to SharePoint using MacroView DMF / Message.

MacroView DMF / Message 8.6.103 and later supports saving emails in the EML format from Outlook. Emails are saved with a .eml extension. This allows emails to be opened by other email applications.

Turning on this feature, all messages are saved with the .eml extension instead of .msg including: 

• Drag & Drop
• Save Message from the right-click menu in Outlook
• Save Message from the Ribbon in Outlook
• When using Save on Send and Send and Save in Outlook
• Run Filing Rules
• Corporate Email Filing
• Predictive Email Filing 

Saving emails in EML format

To save emails in EML format:

1. Go to Options -> Office
2. Check the Save emails in EML format option
3. Click on OK and Apply
4. Restart Outlook
5. All emails will now be saved with the .eml extension

All emails will be saved in the selected format however, MacroView DMF and Message will recognise and open emails of either format regardless of this setting. 

Further Reference

• Saving emails to SharePoint
• Determining where your email is saved on SharePoint