You used to be able to double click on an eml file and have it open in Outlook. Microsoft changed this behaviour in Win 7 and now wants Windows Live Mail to open .eml files. However, many die hard Outlook users don't have Live Mail installed, so it doesn't work.
There are a number of ways to fix that and I've given links below, but all of the fixes seem to deal with Win 7 or 8. I could not find anything for Win 2008 Server, which is what this person is having trouble with. I would have thought that changing the file association would work, but he insists it does not..
I also don't understand why the fixes below mention registry changes - again, I would expect changing file associations would be enough. I don't have Outlook on my Windows 8 machine, but I was able to change eml files to open with Wordpad without resorting to registry changes.