Introduction – EML File Format In Email Clients

MailXaminer | December 26th, 2018 | Forensics

EML is the file extension for single mail message saved in a file containing header, message & attachments. They provide support for non-text attachments & non-ASCII character sets as they follow MIME format.
In Digital Forensics the basic purpose of EML file export is message archiving & sharing as an attachment file across the web. RFC 822 standard format for EML file provides the ease to use these files with a large number of email client, servers & applications.
Extracting email files from Outlook PST file into EML format is the best option when you are using email clients supporting and want to share your data with any particular client. Because EML file only contains sing email data hence it helps to protect the confidentiality of other data.

How EML File Different Form PST File Format?

EML files are individual e-mail message file having a plain text file format which in result gives it a standard file structure. It has a short header having sender, recipient, subject, date & time and the body having the main message.

  • EML follows Multipurpose Internet Mail Extensions format
  • Support for non-text attachments, non-ASCII character sets & message bodies having multiple parts
  • The wide range of accessibility as it supports Windows OS as well as Mac OS
  • Viewed with most e-mail clients like Outlook Express, MS Outlook, Apple Mail, Mozilla Thunderbird etc
  • Directly open in Internet Explorer, Mozilla & Opera by re-naming extension to “.mht” from “.eml”
  • Notepad or text-editor can be used to open EML files

Examine Outlook Database File Format Via MailXaminer

As outlook Email Client stored mailbox information in .pst file format while User’s information stored in a different logical layer of the file. At first, the investigator needs to detect the state of the file, whether it is in a healthy state or not. For that, Hex Editor or MailXaminer can be used to find resulted evidence file.
To know more about, how data stored in PST File format, please visit:

After Analysing the evidence file in PST file, the investigator can create a report with different parameter stored in the file and use the export feature of the tool. If the investigator wants to save all the mail files stored in PST File format as Single File Format, this option also available in the MailXaminer. It provides EML and MSG to save details in single file format and in below section we discuss, how an investigator save PST file information in EML File format.

Examine Outlook PST Files In Different Views: The tool allows the investigator/ examiner to open and examine the Outlook PST file during the email investigation. It provides different views of the email data such as “Mail, Hex, Properties, Message Header, HTML“. Through each view, it provides different information to the examiner other than the normal email message.


Select Specific Mail to Save In EML Format: Instead of saving the entire email file in EML format. The tool provides the option to selectively choose the desired PST file from the mailbox, that needs to export as EML file.

select pst file

Export Options In MailXaminer: Conversion of email data to various file format is possible through the Export Option in MailXaminer. After selecting the desired emails to export choose the EML option to export PST file into EML format.

pst file into eml format

Folder Selection For Conversion In EML Format

When there is a situation for exporting complete folder instead of specific emails as EML file, then you can use the bulk export option of the MailXaminer. Follow the given process to convert a bulk of outlook PST file into EML format.

Export Option: The bulk conversion of PST to EML format is possible through the Export button of MailXaminer. It allows converting the entire folder of PST file to EML format.

export button
Save Selected Mailbox Information in EML File: Through the Export option in the MailXaminer desired folder can be selected to convert PST to EML format. After the folder selection use EML option to export PST file into EML format.

export to eml
Naming Convention Feature: While exporting PST file into EML format the tool provides additional options like “Export setting, Naming convention”. During Naming Convention it provides multiple naming options for the exported file.

naming convention


EML file format is used to export and save the single email messages. In digital Forensics, EML format helps to archive & share single mail message without affecting the confidentiality of the other email data. The Digital Forensic Tool MailXaminer can be used to examine and export PST file into EML format.