I want my users to be able to open eml files in compose mode in outlook 2010, by default it opens in readonly mode. Is there any way out?
Use: We generate email templates which the users can download and customize it before sending.
If you can add the header "X-Unsent: 1" to your .eml, it should open in Compose mode.
Works on Microsoft Outlook but does not work on thunderbird.
A related discussion can be found here https://bugzilla.mozilla.org/show_bug.cgi?id=688284
来源：https://stackoverflow.com/questions/7916318/open-eml-files-in-compose-mode-in-outlook-2010