An EML file is a file format that an email message file that is used by email clients, such as Microsoft Outlook Express. Other email programs that accesses files using the MIME RFC 822 standard format can also use an EML file.
A typical EML file contains email headers and message body using an ASCII text format. Other email elements, such as hyperlinks and attachments, are also stored inside an EML file. This file format can be exported into the a computer hard drive for the purpose of storage and data archiving. The Nimda virus is known to create EML files that can contain viruses or malware.