Converting Outlook email from .msg to .eml files

Screen shot of msg-to-eml conversion software.

EML Viewer Pro is a  versatile Windows software app. You can use it to manage, search and view emails that are formatted in a variety of common formats, including .eml, .msg, .mht, .pst and .ost files.

One of the nice features of EML Viewer Pro is its ability to convert and export email messages from one format to another.  With version 4.7, you can now export email message content to .eml format. .EML files are formatted according to the RFC-822 spec. As an open format, it is supported by most email clients, including Windows Mail and Mozilla Thunderbird.  Because it is an open, non-proprietary format it may be desirable to convert emails into .eml files for archiving purposes.

Here’s how to convert Outlook .msg files into .eml files using EML Viewer Pro.

First, open EML Viewer Pro, and find the folder containing your Outlook .msg files.   Click on the folder, and EML Viewer Pro will read in the msg files and display them in the main list.  Select any listed email message to view it in the reading pane. Double click on an email to open it in full screen view.

Select the emails you want to convert into .eml files.  To select a message, you click on it.  To select multiple messages, hold down the control key, and click on the messages you want.  To choose all of the emails in the list, type Control-A on your Windows keywboard.  Messages that are selected are shown in the list with a blue highlight.

Picture of EML Viewer Pro main menu with msg files selected.
Eml Viewer Pro main screen. Selected email messages are highlighted blue.

When you have selected the emails, you can export them in a single batch operation.  Choose “Export to EML” profile from the toolbar drop down list.

Picture shows how to select the "Export to EML" export profile in EML Viewer PRo
Choose the “Export to EML” profile

To begin the conversion process, click the Export button (the icon with the yellow paper and the green arrow).  EML Viewer Pro will go to work exporting your .msg files to .eml files.

Export process progress bar
Exporting msg files to eml

There is no limit to the number of messages you can export (note: if you are using EML Viewer Pro in trial mode, the limit is 50 emails per export operation. This is removed after the software is purchased).

If you need an flexible tool to help manage your email content, try EML Viewer Pro. It’s several tools in one: view, search, and export.  You can download a free trial and learn more about EML Viewer Pro from the product website.

 

How to Export Outlook Email to .eml or .mbox Format

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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 path e-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.