Email Files – A Primer:

You request emails from your client or opposing counsel, and because you know better – you of course request natives. When the files arrive you are confronted with unfamiliar file formats. What kind of files do these formats represent and now that you have them how do you handle them?


{Disclaimer – This is a very basic reference for those that do not handle email files often. To learn more or to address the advanced handling of meta-data or forensics contact your Lit & More team.}


Meta-data – Data stored in an email about the email. Often this data is not even viewable in the email client application used to create the email. The amount of email metadata available for a particular email varies greatly depending on the email system. (Metadata is not exclusive to email, but emails contain some of the most fascinating metadata of all electronic documents.)


PST – In Microsoft Outlook, the Personal Folders file (.pst) is a data file that stores all of a user’s messages and other items on his/her computer.

Outlook Data Files (.pst) are used for POP3, IMAP, and web-based mail accounts. This is the most common file in which information in Outlook is saved by home users or in small organizations.

MS Exchange files store the individual mail stores (PST) for custodians. One EDB file may contain one or thousands of PST files.


MSG – A .msg file is an individual message. .msg files may be provided if a .pst has been culled or specific messages were identified.


OST – An .ost file is almost identical to a .pst file. .ost files are typically created when a user accesses emails offline in between connecting to an exchange server. An .ost and its partner .pst files may contain different information depending on the last time the user synced their off-line device with the server.


MBOX – An MBOX file is a container of email messages similar to a PST. Many different email clients use variations of the MBOX format, including Mac mail, Eudora, and Mozilla.


What now?

Now that you know you are holding a virtual treasure chest of information, contact Lit & More and allow us to do a preliminary exam of data. We can quickly determine the volume you are working with and propose several different options. Whatever you do – PLEASE never attempt to use Outlook for your review.

Email Files – A Primer


EDRM has been a resource for litigation support professionals and the Lit & More team for more than a decade. Much of our learning and growth over the years can be attributed to EDRM and their amazing resources. Many of the definitions on this page are drawn from EDRM and we encourage you to visit the EDRM site and consider membership. EDRM (


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