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MBOX vs PST File Format

Different email clients use different data file types to save and migrate the mail. Two of the most well-known file formats for working with message databases are MBOX and PST. Let's see how these data files differ and how you can change one format to another.

What is the MBOX file format

MBOX is a data file format for storing all messages from a mailbox or folder. It is one of the most popular formats for storing email message databases.

Many email clients such as Mozilla Thunderbird, Mac / Apple Mail, Eudora, and others use the MBOX file in their work. Other applications, such as Gmail, use this format only for backing up and exporting messages.

The MBOX format allows you to store all emails from a mailbox folder in a single file. In this text file, messages are stored in chronological order, one after the other. To view them separately, you must convert MBOX to a different format.

What is the PST file format

PST is a Microsoft Outlook data file. It stores all information about the Outlook mailbox: messages, calendars, contacts, and other items.

PST is an internal Outlook format and cannot be opened or imported into other email applications.

PST data files are used for backups and archiving. You can store all mailbox data in them at once or selectively, segregating the files by type, date, or other attributes. Archived PST files are often created to organize messages or reduce the Outlook storage size.

What is the difference between MBOX and PST


  • The MBOX format is used to store and back up email databases.
  • The PST format is used to store all Outlook mailbox data, including all item types, folder structure and settings.


  • Many email clients use the MBOX format to store and migrate data.
  • PST data files are Microsoft Outlook proprietary files and cannot be opened in other programs.


  • You can save the MBOX file on different media or in the cloud and transfer it to another computer running Windows or Mac OS. Since it is a text format, files with an .mbox extension sometimes can be partially viewed with a text editor, such as Microsoft Word or Notepad.
  • You need a Windows desktop or laptop computer to work with PST files.

File contents

  • An MBOX file stores the messages in EML format with all the data, including attachments. But, although MBOX is designed to store multiple messages, it cannot store the folder structure. Each MBOX file contains messages from a separate mail folder.
  • PST data file contains a complete copy of the entire mailbox or separate folders. It stores folder structure, rules, view settings, signatures, search folders, and other properties and settings, along with complete information about Outlook items.

Working with files in Outlook

  • Outlook uses its own PST format to work with message databases. MBOX data files cannot be opened or transferred to Outlook without third-party tools such as Import messages from MBOX to Outlook or Convert MBOX to PST.
  • Since PST is Outlook's native format, it can be easily exported, viewed, and imported into the mailbox. You can use the built-in Outlook tools or special utilities with advanced settings to export or import PST files.

File sizes

How to convert MBOX to PST

Many popular email clients can export emails to MBOX data files, but Microsoft Outlook does not support the MBOX format. To make MBOX messages available to Outlook or Exchange Server, you must import them into Outlook or convert them into Outlook-standard PST data files. After converting from MBOX to PST, the message database can be connected to Outlook.

There are various methods to export MBOX to PST format, including manual means. However, the easiest way is to convert from MBOX to PST automatically.

The advanced version of the MBOX to PST converter tool is not only easy to use but also has many advantages:

  • Quickly converts any number of MBOX files with no limitations.
  • Supports all MBOX format modifications from any email application.
  • Converts messages from MBOX to PST, losing no data, including folder structure and attachments.
  • Converts MBOX messages to existing or new PST files.
  • Creates new PST files or folders in PST based on specified criteria for convenient message archive organization.
  • Selectively converts MBOX messages.
  • Converts Gmail MBOX emails from Google Takeout with Google labels to recreate folder structure and mark messages.
  • Splits PST files into parts during conversion.
  • Moves processed MBOX emails to another folder to prevent them from being duplicated when converting again.
  • Converts multiple MBOX files from different folders to PST format using command line application.
  • Uses the command line to convert on schedule and create flexible mail migration scripts.
MBOX to PST Converter

How to convert PST to MBOX

As you can see from the MBOX vs PST comparison, the PST format offers many advantages over MBOX but has serious limitations. It is an internal Outlook format, and you cannot export a PST file to any other email application. To migrate Outlook emails to Mozilla Thunderbird and other MBOX email clients, use PST to MBOX conversion.

The advanced version of this efficient PST to MBOX converter tool has a variety of features:

  • Converts PST files of any size and quantity.
  • Accurately imports Outlook emails from PST to MBOX, preserving formatting, attachments, headers, marks and other data.
  • Saves folder structure and can save each PST file separately.
  • Flexibly customizes the names of received folders and MBOX files.
  • Applies additional filters for messages from PST files to convert.
  • Can overwrite existing MBOX files to avoid creating duplicates.
  • Allows you to create complex scripts to migrate different mailboxes in bulk and on schedule with the command line app.
PST to MBOX Converter


Files with the .mbox and .pst extensions have the same purpose: as data files for saving and exporting mailbox data. The main difference is that MBOX is used by various email applications, while only Microsoft Outlook uses PST.

Other differences between the MBOX and PST formats:

  • You can save distinct mailbox items in PST. For example, you can archive only last year's emails or only the address book. An MBOX file can only store messages from a whole folder.
  • One data file is created when you export the entire mailbox to PST. It contains folders and subfolders and keeps their structure. And to save the mailbox folder tree in MBOX, you get multiple MBOX files, one for each folder.

If you are an MS Outlook user, you can transfer the MBOX archive files to Outlook via MBOX to PST conversion. If you need to open a PST file in another email client that works with MBOX, convert Outlook PST to MBOX format.

You can use more Outlook converters and other utilities to work with PST and MBOX files:

File formats differ not only by mail clients. They can be different when saving individual or multiple messages. For example, Microsoft Outlook uses two file types, PST and MSG, while other popular email applications use MBOX and EML.

A more detailed comparison of similar EML and MSG file types is also presented on our blog. Other comparisons:


What is better, MBOX or PST?

The choice of data file format for storing mail depends on the email client you use. Microsoft Outlook only uses the PST format, while MBOX is supported by various applications, including Mozilla Thunderbird, Mac / Apple Mail, PocoMail, Spicebird, Opera Mail and others.

Does Outlook use MBOX?

No, Microsoft Outlook only works with PST files for storing large data sets. And it uses the MSG format for single messages. To import MBOX into Outlook, use an MBOX to PST converter software.

How to open an MBOX file on a PC?

MBOX files can only be opened by some applications, such as Thunderbird or Mac Mail. If you have Outlook installed on your computer, convert the MBOX file to PST and connect the PST file to Outlook.

Do MBOX files store images and file attachments of emails?

Yes, MBOX files store messages in their entirety, along with images and attachments.

How to open a PST file without Outlook?

You can use special tools to convert PST to other formats: PDF, DOCX, or HTML. If you use an email application that supports MBOX format, convert emails from PST to MBOX or separate EML files to view the messages in that app.

How to export Gmail emails to a PST file?

Read our blog with detailed instructions on how to export Gmail to PST files.

How to import a PST file in Thunderbird?

Mozilla Thunderbird uses the MBOX format to import and export emails. To import messages into Thunderbird from a PST file, convert PST to MBOX format.

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