I think that EML files need either Outlook Express or Windows Mail to open.
Normally those are installed on a system. If you save the file to your hard
drive can you double-click on it to open it?
Could be a corrupted attachment. Could be the wrong extension was put
on the file. Could be you don't have Outlook installed although you
asked in an Outlook newsgroup and you have confused Outlook Express as
some lite version of Outlook. Could be the EML handler is not defined
in your registry. Could be you tried to install a trial version of
Outlook and keep your old Outlook but only one instance of Outlook can
be installed within an instance of Windows. Could be ...
The subject is an intro to your post. It is not to be used to describe
and detail your problem. You add the details in the *body* of your
post. A blank body is a blank post. Vague questions beget vague
responses. Read: