How to Convert MSG to MBOX? A Step-by-Step Guide

Written By Md Shoaib
Updated on August 4th, 2025

William Davis Query: “I want to switch all my emails from Microsoft Outlook at my office to Thunderbird on my personal laptop. Now I have a folder full of .msg files from Outlook, but Thunderbird doesn’t recognize them. Is there any method to convert MSG to MBOX format that works with Thunderbird, without losing my email data or attachments?”

Introduction:If you want to switch from Outlook to email clients like Thunderbird or Apple Mail. You might face a file compatibility issue. Outlook stores individual emails in MSG format. Besides that, MBOX is used by many open-source and Mac-based email clients. Since these formats aren’t directly compatible, converting MSG to MBOX becomes essential. This blog will discuss the simple ways to convert MSG Files to MBOX using manual and a professional MSG File Converter. In addition, both methods offer you a quick and reliable conversion with no data loss.

Table of Contents

What Is MSG and MBOX File Format?

MSG: MSG is a file format used by Microsoft Outlook to store individual email messages.

MBOX: It is a single file that stores multiple emails in a format used by Thunderbird, Apple Mail, and other clients.

Simple Steps to Convert MSG to MBOX

Download & install the CloudMigration MSG Converter Tool.
Pick: Select Files or Select Folder to browse MSG files.
Then, you can preview & select the MSG file to convert.
Next, choose MBOX Format as the saving option.
Lastly, apply advanced features & filters. Click Convert.

Quick Solutions:

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Why Export MSG in MBOX?

Here, we explain several reasons to convert their MSG files into MBOX format:

For cross-platform compatibility benefit (Windows to Mac or Linux).
To simplify bulk email management using the MBOX format.
Unlike MSG, MBOX helps to keep attachments and formatting intact.
Moreover, the MBOX format avoids data loss when switching email apps.

Manual Method to Convert MSG to MBOX Free

If you want to convert a small number of MSG files, you can perfrom it using both Microsoft Outlook and Thunderbird.

Firstly, open Outlook and click on the folder where your MSG emails are stored.
Now, select an MSG file and choose the File option.
After that, select Save As, then choose Text Only.
Next, change the file extension from .txt to .eml.
Then, open Thunderbird and install the ImportExportTools NG add-on.
Further, create a new folder in Thunderbird.
Right-click on it and choose ImportExportTools NG > Import EML Files.
Afterwards, browse to the folder where you saved your .eml files.
Once imported, right-click the folder, select ImportExportTools NG.
Choose the Export Folder option and then select As MBOX File.
Lastly, choose a location to save the MBOX file and click Select Folder.

Limitations of Manually Converting .msg Files to .mbox

While the manual method is free to use. But it has several drawbacks that make the process irrelevant for many users:

The process is long and includes many steps, which makes it time-consuming.
There’s a higher risk of losing data or damaging files during the conversion.
It does not support bulk or batch conversions, so you’ll need to convert each file individually.
Also, for users without much technical knowledge, the steps may be confusing or difficult to follow.

However, you can easily avoid these limitations with the alternative professional conversion tool.

Hassle-Free Way to Convert MSG to MBOX: Dedicated Tool

For a quick and bulk MSG conversion, you can directly use the CloudMigration MSG Converter Tool. This utility is specifically tested and suggested by many experts. It helps you convert multiple MSG files to MBOX without data loss or minimal disruption. Also, it maintains the data’s originality, privacy, formatting, and structure throughout the conversion. With its simple interface, every user (Tech & Non-Tech) can easily use it without any technical skills. Apart from MBOX, this tool convert MSG to PDF and other file formats without any hassle.

How to Export MSG to MBOX Professionally?

Firstly, download and install the CloudMigration MSG File Converter Tool.
Now, you can pick either Select Files or Select Folder to add the MSG files.
Then, use the preview feature to cross-verify the MSG files and select them.
After that, you can choose MBOX as a Saving Format from the given list.
In the end, apply advanced features as per your needs. Click Convert.

Why Choose CloudMigration MSG Converter Tool?

Offer One-Time Service
For a more customized and cost-effective solution, you can request a one-time MSG to MBOX conversion from our technical support.

Compatible With Several Formats
This tool helps you convert MSG Files to Outlook PST and other email clients, like Thunderbird, Gmail, etc.

Demo Version Available
The demo version (FREE) of this tool is available to evaluate its performance and functionality. Also, highly compatible with all Windows versions.

Conclusion

In this detailed blog post, we explored the two top methods to convert MSG to MBOX online. One is a manual method that uses Outlook and Thunderbird to perform this conversion. Also, it is only used to convert a few MSG files. Another is a professional tool that converts multiple MSG files simultaneously. This solution offers 100% accurate conversion without any data loss or errors.

Frequently Asked Questions

Q1. What are the prerequisites to keep in mind before converting MSG to MBOX?

Ans: Ensure your MSG files are not corrupted and stored locally. Also, close Outlook before starting the conversion to avoid file access issues.

Q2. Which is the best tool to convert MSG to MBOX?

Ans: The CloudMigration MSG to MBOX Converter is a reliable and easy-to-use tool recommended for safe and batch email migration.

About The Author:

Md Shoaib

Hi, I’m Md Shoaib! I enjoy writing about technologies and helping my readers with their queries, and I’m always looking for new ways to challenge myself and grow. Professionally, I work as a Digital Marketer, where I specialize in SEO and Copywriting.