How to Convert EML to MBOX for Windows and Mac OS?
If you’re moving your email archive from Microsoft Outlook to a Mac-based client like Apple Mail or Thunderbird, you’ll likely need to convert your old EML files to MBOX format. This applies whether you’re switching operating systems entirely or just switching email clients on the same machine. A dedicated EML to MBOX converter handles this conversion for Windows and Mac, without you needing to touch each file by hand.
What Is MBOX, and Why Do You Need It?
MBOX is a file format. It stores multiple email messages in a single file.
Clients like Thunderbird, Apple Mail, and most Linux-based mail systems use it. It’s been around since the early days of Unix email, so it’s a long-standing standard, not a new or proprietary format.
EML works differently. Each EML file holds just one email. So if you have thousands of emails, you have thousands of EML files.
That’s the real reason people convert EML to MBOX format. One file is easier to archive, back up, or import into a new client. It’s also required if you’re moving from an Outlook-based setup to a Mac Mail or Thunderbird environment, since those programs expect MBOX, not EML.
Convert EML to MBOX Using Thunderbird for Free
You don’t need paid software for a small batch. Here’s a free way, using Mozilla Thunderbird.
What you’ll need: Thunderbird installed, plus the ImportExportTools NG add-on (free, from Thunderbird’s add-on store).
- Step 1. Open Thunderbird and go to the add-ons manager.
- Step 2. Search for “ImportExportTools NG” and install it.
- Step 3. Restart Thunderbird once the add-on finishes installing.
- Step 4. Create a new local folder in Thunderbird to hold your imported emails.
- Step 5. Right-click that folder. Choose “ImportExportTools NG,” then “Import EML file(s).”
- Step 6. Select your EML files and import them into the folder.
- Step 7. Once they’re in the folder, right-click it again. Choose “Export folder,” then save it as an MBOX file.
That’s it. Thunderbird handles the conversion in the background.
Note: It’s fine for a few dozen emails, but slow and manual for large archives. You’re importing one folder at a time, and there’s no batch automation. For hundreds or thousands of EML files, dedicated EML to MBOX converter software is faster and far less tedious.
Software to Convert EML to MBOX on Windows & Mac OS
FreeViewer provides a dedicated EML Converter tool to export EML files to MBOX file format with all attachments. The software is developed with a simple and easy-to-understand user layout. This utility also has a number of advantages. Any type of user can directly export to the MBOX file format.
EML to MBOX Conversion Software’s Best Features
Get the best and highlighted features of the conversion tool:
- Migrate multiple EML or EMLX files in bulk to MBOX format
- Support converting EML files to PST, HTML, TXT, MSG, PDF, EMLX on Mac/Windows OS
- Safely transfer email data with attachments to output file format
- Add folder option to convert multiple EML files to MBOX on Mac/Windows OS
- Convert EML to MBOX format on Mac without any size limitation
- Maintain integrity of email data and attributes through formatting
Steps to Convert EML to MBOX on Windows OS
Perform the steps listed below irrespective of Windows OS versions. The software is compatible with the latest Windows 11 and all versions below.
Step 1: Download the EML to MBOX converter tool and launch it on a Windows OS system.
Step 2: Browse the EML/EMLX file and preview its contents in the software panel.
Step 3: After verifying the EML file data, simply click the Export button and select the MBOX radio button. Apply required advanced settings and browse the path to save the output MBOX file.
Step 4: After completing the conversion process, the software will display a success message in a pop-up. 
Steps to Convert EML/EMLX to MBOX in Mac OS X
Mac OS users can follow the steps listed below and easily export complete data from EML to MBOX file format. This ensures complete data conversion:
Step 1: Download and install the EML to MBOX converter for Mac and launch it.
Step 2: Use the file or folder option to browse EML and EMLX files into the software panel.
Step 3: Next, preview the loaded EML or EMLX file on the software screen
Step 4: Select the MBOX radio button from the export options. After this, apply advanced settings and browse the path to save the output MBOX file.
Step 5: The software will start the export process and display a success message in a new pop-up.
Convert EML to MBOX – FAQs
Q: What is the MBOX format used for?
Answer: MBOX stores multiple emails in one file. Thunderbird, Apple Mail, and many Linux email clients use it. It’s a common choice for archiving or migrating large volumes of email.
Q: Does converting EML to MBOX cause data loss?
Answer: Not if you use a reliable method. A good converter preserves attachments, headers, and read/unread status. Free manual methods, like Thunderbird, also work well for smaller batches.
Q: Is there a free way to convert EML to MBOX?
Answer: Yes. Thunderbird with the ImportExportTools NG add-on works for free. It’s best for smaller batches. For large-scale conversion, paid software saves time.
Q: Can I convert EML to MBOX without using Outlook?
Answer: Yes. You don’t need Outlook at all. Thunderbird and most dedicated EML to MBOX converters work independently of Outlook.
Q: Does MBOX conversion work the same way on Windows and Mac?
Answer: Mostly, yes, though the software and file paths differ slightly between the two. Mac Mail and Outlook for Mac also store data differently than Windows versions, so some converter tools offer separate Windows and Mac builds to handle that.
Q: How long does it take to convert a large batch of EML files?
Answer: It depends on file size and volume. A few hundred small emails usually convert in a few minutes with dedicated software. Manual methods take much longer since each folder is handled by hand.
Conclusion
The software is specially designed to convert EML to MBOX mailbox format in batch, saving users time and effort. Before purchasing the tool, users can test it through the free trial version. One of the best features of this product is that it is compatible with all the latest Windows and Mac operating systems.