Opening .eml files from SharePoint 2007 in Outlook 2010

When an email is sent to an email-enabled library in SharePoint 2007, the email gets saved as a .eml file. 

Opening the email from SharePoint using Firefox results in the email being downloaded to the client's computer and opened in Outlook 2010 - Firefox doesn't know how to handle a .eml file and defaults to downloading the file. The OS knows to open a .eml file in Outlook 2010 and so the desired behavior is achieved. 

Opening the email from SharePoint using IE results in the email being opened in an IE window - problematic because the user loses the ability to view email attachments, reply to the email, forward the email, etc. The quickest fix to this issue is for the user to download the email (a choice from the ECB menu in the library) but I prefer a fix that doesn't require the user to do anything ... better experience for users, no chance for users to make a mistake, whatever reason suits your fancy.

Turns out that .eml files opening in IE is regulated by the following registry key:

HKEY_CLASSES_ROOT\MIME\Database\Content Type\message/rfc822 

To stop .eml files being opened in IE, delete the registry key on the user's computer ...

1. Start the Registry Editor - 'regedt32.exe' in a command prompt window
2. Backup registry key stated above
3. Delete registry key stated above

This can be done using Group Policy and a startup script.