I came across a problem today where some co-workers were forwarded a bunch of emails that were attached as files, instead of inline, but they couldn’t open them. They kept trying to open in Outlook Express, which we don’t use. I could have just let them open all the attachments in Outlook Express, it wouldn’t have been a huge deal. But if they wanted to respond back to them they would have to bounce back and forth between the two – slightly annoying. I googled and found this website where you can download the registry key that allows you to open the .eml files in Outlook 2003 or 2007. You just have to make sure you install the key for the correct version of Outlook and either the 32 or 64-bit version of windows (most of you are probably 32-bit).
Before you install the key, you have to make sure you have all the current windows updates associated with Outlook, it won’t work if you don’t. After you check for updates, all you have to do is download the zip file, open it, and double click on the version that matches what you have – the key will install itself. You don’t need to restart the computer and I don’t think you even need to restart Outlook, if it was open. The .eml attachment should now open in Outlook without any problems.
If the link for the .zip file on that website ever dies, I uploaded it here.