How to Open EML File Types
It's rare to run across a stand-alone .EML file. Email programs create the files whenever you choose to forward a message as an attachment rather than including the original text in the body of the forwarded email. As such, .EML files are typically connected to a message you receive in your inbox. If you do stumble across a stand-alone .EML file, you have a few different options. The easiest thing to do would be to try to open it with an email program, but if you don't have one, you can reclassify the file's extension and open it in a Web browser.
Open With Email Program
Browse to the .EML file's location on your computer.
Right-click the file and select "Open With." A window with a list of suggested programs to open the file with appears.
Choose an email program, such as Outlook, Outlook Express, Windows Live Mail, Thunderbird or IncrediMail, and then click "Open." The .EML file opens in the selected email application.
Open With Web Browser
Drag the .EML file into a folder if you don't have an email application. Open the folder.
Click on "Tools" in the folder's toolbar, then select "Folder Options." Open the "View" tab in the folder options. Remove the check in the box next to "Hide Extensions for Known File Types," then click "OK."
Right-click on the .EML file and select "Rename."
Erase the ".EML" extension, then replace it with ".MHT" and press "Enter" on your keyboard. Confirm that you want to make the change when Windows informs you that you may be altering the way the file is recognized.
Double-click on the file. It opens, in viewable format, in your default Web browser.