Microsoft Outlook Express mail message (MIME RFC 822)
EML files can contain plain ASCII text for the headers and the main message body as well as hyperlinks and attachments.
EML files may be exported for the purposes of archiving and storage or scanning for malware. The Nimda virus is known to create EML files. When EML files are found as an included attachment it is good practice to scan with anti virus before opening.
MIME type: message/rfc822
Learn more about EML files:
See the F-secure Nimda virus description page
Ed Yakabovicz Talks about cleaning the Nimda virus and Identifying EML files at Search Security.
Search for answers to email storage related questions at IT Knowledge Exchange.