MBOX is an email format that holds collections of email messages. In the MBOX mailbox, all the messages are concatenated and stored in a single file as a single, long text message. Each message starts with “From,” followed by space and the email address of the sender. There are four variants of MBOX viz. mboxo, mboxrd, mboxcl and mboxcl2. Mboxo and mboxrd find the starting of the message by scanning word “From” which is present before the header of the email message. There may arise ambiguities while locating the message when “From” is present in the body of the message. In mboxo format, this ambiguity may result in corruption of the message, whereas mboxrd format converts the “From” in the message to “>From” and “>From” to “>>From.” Mboxcl and mboxcl2 formats, on the other hand, use content length.

Different Email clients use different formats like Eudora uses mboxo, Mozilla, Netscape, and Thunderbird uses mboxrd. We are now going to discuss the best free MBOX viewer applications and their salient features so that you can make a choice as per your requirements.

What should one expect from a good MBOX viewer?

A good MBOX viewer should be able to view, read, export, and print healthy and corrupt MBOX file messages and attachments. It should be able to search messages using various filters like, From, To, sender, content, date, etc., easily and quickly. It should support maximum email clients, all versions of Windows and Mac. It should be able to save data in maximum file formats.

Best Free MBOX Viewer Tools

Considering the above-stated features, we have tried our best to explore the best Free MBOX viewer tools described below. Some advanced features are always provided by the upgraded version or Pro version only. We have tried to compile some of those giving maximum features though the list is long.

  1. Kernel MBOX Viewer
    Kernel MBOX Viewer is an efficient and easy-to-use tool for viewing and reading MBOX files.

    Download

    Features

    • Can view MBOX emails of 20 email clients without any need to install any email client. These are Apple Mail, Web Mail, Evolution, Sylpheed, Thunderbird, SeaMonkey, Spicebird, Mulberry, PowerMail, Entourage, Netscape, PocoMail, GyazMail, Claws Mail, Eudora, Opera, Postbox, Gnu, The Bat!
    • Shows a detailed preview of email and other items of the file.
    • Can search email easily with the help of filters like To, Subject, From, Time, Date, etc.
    • Can add one or more MBOX file(s) to view the email data.
    • Can save the list of displayed MBOX files in HTML format, which can be opened in web browsers.
    • Support all versions of Windows, including Windows 365 and 11, and Windows Server 2019, 2016, 2012, 2008R2, 2008, 2003R2 & 2003. This feature makes it more desirable as compared to other tools.

    Demerits

    • To import MBOX emails to Outlook, save MBOX data to DBX, MSG, EML, PDF, TXT, HTML; save MBOX emails to email servers, viz. GroupWise, Exchange & Domino; or export MBOX files to Office 365; you need to upgrade the version.
    • It does not repair corrupt email files.
  2. Aryson MBOX Viewer
    It is an easy-to-use yet efficient tool for viewing MBOX files and attachments.

    Features

    • Can open and read healthy as well as corrupt MBOX files and attachments.
    • Can browse email messages by range of dates.
    • Can preview MBOX Emails, Notes, Tasks, Contacts, Calendar, and other items in the mailbox.
    • Can view and open attachments in Google Takeout and Google Vault (.mbox) files.
    • Can view MBOX/MBX/MBS files created by different email clients like Apple Mail, Thunderbird, Spicebird, Netscape, Entourage, Incredimail, Google Takeout, Postbox, Mulberry, Opera Mail, etc.
    • Supports Windows 10, 8, 7, 2003, XP, and Vista.

    Demerits

    • To open an MBOX file with Outlook, you need to save the MBOX file to a PST file, for which you need to take the help of the MBOX to PST Converter tool, and this feature is available in the upgraded version.
    • You can export Mbox file emails into Outlook PST files in the upgraded version.
    • You can save MBOX files into PST, EML, MSG, HTML, and RTF format in the upgraded version.
  3. SysTools Free MBOX Viewer
    This tool is an efficient yet easy-to-use tool designed to view MBOX/MBS/MBX files of many email clients without depending on them.

    Features

    • Can view and read emails and attachments.
    • Can view and read MBOX/MBS/MBX files of various email clients like Netscape, SeaMonkey, Evolution Mail, Eudora Mail, Thunderbird, Opera Mail, Entourage, Apple Mail, etc.
    • Can view and read MBOX files without depending on the email client.
    • Can view single/multiple file/files using file mode or folder mode, respectively.
    • Deep analysis of MBOX emails for forensic purposes.
    • Supports Windows 11, 10, 8, 7.

    Demerits

    • The advanced search feature, which enables searching a file using a search filter, is available in the Pro version.
    • The export feature, which enables you to save MBOX files in Portable Document Format, is available in the Pro version.
  4. Windows MBOX Viewer
    Windows MBOX Viewer is software that discovers messages based on content.

    Features

    • Can view and read emails and attachments irrespective of the size of the file.
    • Can search by date, subject, sender, mail text, and name of the attachment.
    • Can export single/multiple/ all emails to separate email files.
    • Can export attachments.
    • Can export single /multiple/ all mails to text, PDF, HTML or CSV files.
    • Supports Gmail Labels & Thunderbird exports.

    Demerits

    • It can be reported as malware by Windows Defender.

Conclusion

In this blog, we tried to discuss the MBOX format and its various forms, and how they are read by various MBOX viewers. We hope you found an efficient MBOX viewer through their features.