Free Add-ins for Microsoft® Outlook®


What Our Users Say : : :

"Used to import my old .eml files - worked a treat thank you."

"Worked like a charm. Brilliant tool."

"It worked very well, thank you! "

Follow Us : : :

Convert MSG to MBOX

Convert MSG to MBOX
Converts Outlook MSG message files to MBOX format. It is possible to retain the original folder structure.
Version: 4.21 released on May 11, 2023.
(4.7 / 128 reviews)

Convert MSG to MBOX for Outlook
You can download a free limited version down below

This utility converts email message files from internal Outlook MSG format to common MBOX format. During the conversion, it preserves the original folder structure, email message data, metadata, and attachments.

Main features

  • Converts any number of MSG files to one or multiple MBOX files.
  • Retains the original messages unchanged during conversion, including the message headers, properties, and attachments.
  • Supports all versions of Outlook starting from Outlook 2007. 
  • Allows you to convert messages for a certain time period. 
  • Automatically arranges the resulting MBOX files into folders using ready-made macros, keeping the converted messages organized and easy to find.
  • Can preserve the original directory structure of the folders with source MSG files. 
  • Supports batch MSG to MBOX conversion using the command line possibilities. The option is included in the Professional Version of the utility. 
  • A user-friendly interface makes it easy to customize the software, even for inexperienced users.

What is MSG format?

MSG is a file format used by Microsoft Outlook to save individual email messages, calendar events, contacts, tasks, notes, journal entries, and other Outlook items. An MSG file contains all the message data and metadata: text, attachments, the sender's name, the date the message was sent, and so on.

What is MBOX format?

MBOX is a file format used by many email clients, including Mozilla Thunderbird, MAC/Apple Mail, Opera Mail, and others. This format is designed to store, import, and export email databases. Some cloud services like Gmail use the MBOX format to upload messages. It stores all messages from a folder or a mailbox in one file.

What is the difference between MSG and MBOX?

MSG files are used by Microsoft Outlook to save individual email messages. MBOX files are used by different email clients to store multiple email messages in a single file. Most email systems can import messages from MBOX files but do not work with the MSG format used only by Microsoft Outlook.

Why do you need to convert MSG to MBOX?

MSG is a native Outlook format. No other email client works with it. Converting MSG to MBOX format allows users to access their Outlook messages in other email clients. Additionally, converting scattered MSG emails to one MBOX file makes it easier to back up or transfer multiple messages.

How to convert MSG to MBOX manually

Manually converting MSG to MBOX requires advanced knowledge of file formats and email clients.

The process of manual MSG to MBOX conversion typically involves the following steps:

  1. Open the MSG file in Outlook. 
  2. Use the "File > Save As" option to export the MSG message to EML format, saving the EML file to your computer.
  3. Repeat Steps 1 and 2 for all MSG files to convert.
  4. Import the resulting EML files into an email client that supports MBOX. Open the email client and use the "File > Import" option to import the EML files.
  5. Export the EML files to MBOX format. Once the EML messages have been imported, use the "File > Export" option to export them to MBOX format.

It's important to note the downsides of the manual way:

  • It is a time-consuming and complex process. 
  • This method is prone to errors, especially if you are not familiar with email formats and applications.
  • It doesn't always work seamlessly with every email client and file version. 
  • It may not preserve the file metadata and attachments, resulting in the loss of important information.

It's highly recommended to use specific software for the MSG to MBOX conversion.

Pitfalls of MSG to MBOX online conversion

Even though online conversion tools seem to be easily available and quick, they also have some major drawbacks:

  • There is a serious risk of data loss because you expose your files to third parties. MSG files contain important confidential data. When you use an online service, all this data is transferred to an external server. This does not happen when converting on your local machine.
  • Online converters may not maintain the integrity of the original files, causing important information to be lost. 
  • They may not have the same level of MBOX compatibility and support as dedicated conversion software, leading to file corruption.
  • Online conversion requires a fast and stable internet connection, especially if you have many files to convert.
  • Bulk online conversion may be too costly. The cost depends on the message's overall number or size. When converting offline, the file size or number does not matter. You only pay to install the converter.

Additionally, online conversion tools may have limitations on the size and number of files that can be converted at one time. They may also require payment for larger files or more advanced features. Furthermore, online converters may not provide detailed control over the conversion process, which can result in poor-quality output or missing data.

In conclusion, it is important to weigh the pros and cons of using an online conversion tool for MSG to MBOX conversion and consider using a dedicated conversion software for better control, security and quality.

How to convert MSG to MBOX automatically

Using this automated conversion software ensures an efficient conversion process. Select the MSG files you wish to convert, make a few simple settings, and the software will handle the rest.

Benefits of the automatic conversion from MSG to MBOX

  • Preserves the integrity of the original messages, including headers, formatting, attachments, and all email metadata. 
  • Creates separate .mbox files for each folder with .msg files according to the original structure. 
  • Automatically organizes MBOX files into new folders according to the predefined parameters.
  • Customizes MBOX file names when converting from MSG.
  • Enables batch conversion from multiple user profiles.
  • Overwrites existing files.
  • Use the date range filter to pick up messages for conversion.

Steps to convert MSG to MBOX

  1. Start the Convert MSG to MBOX utility from the ReliefJet Outlook tab or a standalone application.
  2. Select the folder with MSG files to convert.
  3. If the “Include subfolders” box is checked, you can re-create the structure of the folders with the source MSG files.
  4. Choose the destination path for the resulting MBOX file or folder. 
  5. Use macros to create new subfolders named according to the specified parameters. This feature allows you to automatically organize the resulting MBOX files into folders by the sender, subject, date, etc.

    Regular expressions are available for advanced users. They can extract only the desired fragments of the subject, message body, and other fields of Outlook email messages for the target folder name and saved files. 

  6. If needed, select the “Overwrite existing files” and “Use Internet transport headers” options. 
  7. Apply a period filter from the list to select files to convert. 
  8. Click Run to begin the process.

Bulk MSG to MBOX conversion

The command-line app in the utility Professional Edition is designed to select and convert any number of MSG files from multiple user profiles at once. The app allows you to use PowerShell scripts, batches, and other automation tools. It is an excellent solution for complex email migration issues.

If you run several command-line applications at once, the automatic conversion of many .msg files to .mbox becomes much faster due to the parallel execution.

To schedule email conversion from MSG to MBOX, use the command line app and the standard Windows Task Scheduler. The scheduler allows you to flexibly configure the schedule parameters and run the utility without manually logging into a user account.


How do I convert MSG messages to MBOX?

You can convert MSG to MBOX in 3 steps:

  1. Select the folder with MSG files to convert.
  2. Indicate the path for the MBOX file or folder. 
  3. Click Run to begin the process.

If needed, use the software's advanced settings:

  • Re-create the source folder structure 
  • Organize the final MBOX messages into new folders using macros.
  • Overwrite existing MBOX files
  • Use Internet transport headers
  • Select messages for a specific period. 

Can I convert multiple MSG files to MBOX at once?

Yes. The software allows you to convert MSG files to MBOX in bulk, saving time and effort. If you installed a Professional Edition of the utility, you could use the command-line app for mass and batch MSG to MBOX conversion.

Are there any risks of data loss or corruption during the conversion process?

The converter preserved all the email data, including headers, formatting, message flags and statuses, images, and attachments.

Unlike online converters, locally-installed software is absolutely safe. The original files remain intact, so data integrity is guaranteed.

How to open MSG files without Outlook?

MSG format is intended for use only in Outlook. You can open MSG files in other email programs after converting them to another format. The MSG to MBOX converter changes the Outlook message format to one that is compatible with third-party email clients such as Apple Mail or Thunderbird.

Are there any limitations when converting MSG to MBOX?

There are no limits on the number and size of files to be converted and received. You can convert an unlimited number of folders or files and do so as often as you like.

Can I save MSG contacts to MBOX?

Since MBOX is a format for storing email messages only, contacts, calendars, and other Outlook items will not be stored in it.

How to open .MSG files on Mac?

Unfortunately, you cannot open Outlook MSG files on Mac by standard means. When you try to open an MSG file in Apple Mail or Outlook for Mac, you get a new email message where this MSG file is added as an attachment you cannot view.

Converting messages from MSG to MBOX is often the only way to open MSG on Mac.

After conversion, you can load messages from MBOX to Apple Mail using standard import tools. Use File > Import Mailboxes in Apple Mail to import messages from MBOX.

How to open MSG files without Outlook?

Files in MSG format can be opened in Outlook. To open MSG files in other programs, you need to convert them to another format. After converting MSG files to MBOX format, you can load messages to third-party email clients such as Apple Mail or Thunderbird.

OutlookFreeware.com Outlook Ribbon
All utilities easily integrate with Outlook (optionally)

* This utility is for non-commercial home use only. It will not run in domain enviroment. Some of the described features and support for domain enviroment are available in advanced version of the utility only. Free version may have additional limitations.

Recent Blog Posts : : :

Merge Outlook PST Files without Duplicates
It is very convenient to store different Outlook data in separate PST files. But over time, users accumulate a lot of scattered data files. Then, for different reasons, it may be necessary to merge them.

Transfer Outlook Folders to a New Computer
Microsoft Outlook allows you to move information to another desktop by using PST data files, or by synchronizing the account with an email server. But what if you only need to move certain Outlook folders to a new computer?

Merge Folders in Outlook
With an extensive Outlook folder structure, users often have the task of merging folders between or within different email accounts. Let's find the easy way to complete the task.

Move Folders in Outlook
In Microsoft Outlook, you can create a convenient extensive folder structure to organize messages, contacts, calendar events, and other mailbox items. These folders can be moved within and between accounts. This article explains the manual and automatic ways to move folders in your Outlook profile.

Move Emails Between Folders in Outlook
You can create Outlook rules to automatically allocate emails to new folders. But to relocate messages and change the folder structure, Outlook does not offer automated tools. Let's see how you can move or copy emails manually and in an alternative manner.

More in blog...

Trusted Software : : :

110 Power Add-Ins for Outlook

© 2010-2023 Relief Software. All Rights Reserved. Privacy Policy  |  Terms of Use  |  EULA