Open .EML Format Documents With EML Viewer Pro Software

Documents with the .eml extension creep into our work and lives from many different vectors. This article discusses what these files are, how to open .eml files, and software to search and manage large quantities of them.

What are .eml documents?  

.Eml document files are emails that contain the message and any file attachments accompanying the message. EML documents have been part of the internet for more than thirty years. They are formatted according to an open standard published in 1982 called RFC-822. This standard put forward the rules that has helped software developers create interoperable email clients such as Outlook Express, Windows Mail, Thunderbird, and others.

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How do I open .eml documents?
EML files are well supported across nearly all email clients, and it is not too difficult to find software to help you open them individually.  If you only have a few .eml documents that you would like to open, try this free online eml file viewer operated by Encryptomatic LLC. Upload your .eml file and then click “view,”  and it will appear in your web browser. File attachments in the email can be downloaded to your computer.  All uploaded emails are destroyed when your session ends, and no information is collected from the emails.
Image shows MessageViewer Online, rfc-822 compatible eml document viewer.
Open EML Documents In Your Browser With MessageViewer Online

While MessageViewer Online is perfect for opening a few .eml documents, if you want to manage thousands of them you’ll want a more specialized Windows software to handle the chore.

EML Viewer Pro is an advanced viewer for opening and searching eml documents. It can read Windows directories containing thousands of files,  rendering them in the viewing pane in their regular text or html formatting, and providing access to any accompanying file attachments.  
While there are many applications that an open individual files, EML Viewer Pro excels at managing larger quantities of eml documents.
Image shows Eml Viewer Pro document viewer main screen with an html email rendered.
Eml document viewer
Searching a folder with hundreds or thousands of .eml formatted documents is easy with EML Viewer Pro.  Select the folder where your eml docs are located, and the click the search button. A form will appear where you can enter in your search criteria. You can perform a search across the subject, text, or search a date range.
Search options in Eml Viewer Pro. Enter search settings for .eml files.
Once you have located the .eml documents that are important to you, EML Viewer Pro will let you process those messages individually or in bulk. You can print them, or convert them to .pdf format, or a wide range of other formats.
Image shows export profile selection in Eml Viewer Pro.
Convert Eml Documents to PDF and other formats

How to export Outlook email to .eml or .mbox format

What are .PST and .MBOX files?

Pst files and Mbox files both email messages.  While PST files proprietary to Microsoft Outlook, Mbox is an open specification used by email clients such as Mozilla Thunderbird.  RFC-822 and subsequently RFC-2822 are the open specifications documents that describe internet messaging and embody the structure of .eml files.   An MBOX file is a “mailbox” file which contains a collection of RFC-2822 email.  So .MSG is to .EML what .PST is to .MBOX.

RFC-822 was not directly adopted by Microsoft Outlook, the leading email client software in the world. Outlook email messages are stored in a single .PST file which may contain thousands of individual emails, messages including their file attachments. The specification for  creating a .pst file is proprietary, and is determined by Microsoft Corporation. The .pst specification was closed until Microsoft began publishing parts of the specification in 2010.
When Outlook exports a single email item from a .pst file, it is saved as a .msg file, which is also a proprietary Microsoft specification. Outlook .msg and .pst files requires Microsoft Outlook, or an Outlook viewer such as PST Viewer Pro.
Emails within a .mbox mailbox are concatenated and stored as in plain text. The start of a message within the .mbox file is delineated by a line with the word “From” followed by a space and the return pathe-mail address. 
Because RFC-822/2822 is an open specification it has been adopted by email client software such as Mozilla Thunderbird. It is still used to store and exchange email messages. Some companies prefer to store emails in this open standard, rather than in a proprietary standard.

Exporting Outlook to .EML/.MBOX

Microsoft Outlook does not directly support exporting email messages from a .pst or .msg files to .mbox or .eml files. To do this requires a third party add-in extension to Microsoft Outlook.
MessageExport is a useful add-in for Microsoft Outlook for exporting email messages to formats that missing from Outlook. MessageExport integrates tightly with Outlook’s main toolbar to allow users to select email messages from within Outlook and then export the emails directly to .eml or .mbox format.
Choosing the "Export to .eml" email export function.
Export to .EML from Outlook toolbar
In addition to .eml and .mbox, MessageExport also adds other export formats to Outlook, such as .pdf, .msg, mhtml, gif, tif, text, html, and many others.
Image shows dozens of email export operations that can be performed by MessageExport add-in for MS Outlook.
Export formats included with MessageExport
To export Outlook emails to PDF with MessageExport, click a message or messages in the Outlook message list so that they are highlighted. Next, select the export format from the MessageExport dropdown list (.eml or .mbox) and then click the Export button.  MessageExport may ask you to select a target folder, and once done will begin to export the selected emails.
If you export to .mbox, then all of your selected Outlook emails will be in a single .mbox file.
If you export to .eml, then you will have one .eml file for each Outlook email that was selected.
MessageExport also includes a “drag and drop” conversion capability.  Using MessageExport’s Export Folder Explorer, you can immediately convert a message to the selected format just by dragging that file and dropping on a folder in the explorer.
Drag and drop email conversion from MS Outlook.
Export folder explorer in closed state, resides on the right-hand side of the Outlook window. To use it, click to expand.

Selecting the appropriate folder for despositing email that has been converted.
Export folder explorer in expanded state.  Drag and drop email messages on the selected folder to immediately convert it to the currently selected format.
 MessageExport is a useful add-in for convert Outlook email message to .eml, .mbox, .pdf and other formats that are not natively included with Microsoft Outlook.  You can download a free 15 day trial of MessageExport.