How to Convert PST to MBOX – A Step by Step Guide

Updated On - October 25, 2023 by Henry Bray | Reading Time: 4 minutes

These days, many emails and email handling software offer users to work with any email client; if we talk about them, it is impossible not to have heard of MS Outlook – it is one of the most popular and especially preferred email clients for Windows. And Outlook is the best email client for businesses, corporate, organizations, individuals who manage more than 1000 emails a day. Although MS Outlook is also a version for the Mac platform, it is not very popular among Mac users. In this blog post, we will guide you through the process to convert PST to MBOX using a third-party tool, as well as some manual methods.

If you’re looking to switch from Microsoft Outlook to another email client that supports the MBOX file format, you may need to convert your PST files to MBOX format. PST files are the proprietary file format used by Microsoft Outlook to store email messages, contacts, calendars, and other data. MBOX, on the other hand, is an open-source file format used by many email clients to store email messages.

Most Common Reasons to Move Data from Outlook PST to MBOX files

Let’s focus on the most common reasons why many users want to convert Outlook PST files to MBOX file format supported by various email clients, including Thunderbird, Spice Bird, Eudora, Apple Mail, etc. Here we have mentioned a few reasons below, so after reading all these reasons, you will know why users need MS Outlook to MBOX conversion.

  • In the long run, MS Outlook proves to be very expensive for many general users. It becomes necessary for users to purchase a licensed version of MS Office after a certain period. You can download MS Outlook and sign up during the trial period to evaluate the product, but after that, you will need to purchase a license for it.
  • Therefore many users want to shift from MS Outlook to MBOX supported email clients for free. Desktop email clients, which are available both open source and online for free, are preferred by single users.
  • PST files in MS Outlook can be corrupted and inaccessible. When we talk about Microsoft products, we do not find any native method of resolving file loss or corruption issues, and PST only works on MS Outlook. Thus, if the file is corrupted once, then in this situation, we may be stuck for a long time.
  • Outlook users must have Windows OS enabled, and MBOX files can be accessed on any OS. For example, Windows, MacOS, Linux, etc.

You are clear about why and when users might need the Outlook PST file conversion to MBOX file format, and I hope you also came to know the main differentiation between the two file formats. Now we come to the next topic how can you convert a PST file to MBOX?

Convert PST to MBOX Files by Manual Way

There are a few manual methods available to convert PST files to MBOX format, Before go to the manual method make sure your system have Installed MS Outlook and Thunderbird email client. Because this method use these 2 email clients to convert PST to MBOX files. 1st step using MS Outlook and in 2nd step using Thunderbird email client. Lets start.

Step 1: Export PST File(s) to EML Format

  • First, export the PST file(s) to EML format in Microsoft Outlook. To do this, open MS Outlook and select the PST file(s) that you want to convert.
  • Click on the ‘File’ tab and select ‘Import and Export.’
  • In the Import and Export Wizard, select ‘Export to a file’ and then select ‘Outlook Data File (.pst).’
  • Choose the PST file that you want to export and then select ‘EML’ as the file type.
  • Choose the destination folder where you want to save the EML files.

Step 2: Import EML Files into Thunderbird

Once you have exported the PST file(s) to EML format, import the EML files into Mozilla Thunderbird. To do this

  • Open Thunderbird and click on the ‘Tools’ menu.
  • Select ‘Import’ and then select ‘Mail’ to import EML files.
  • Choose the EML files that you want to import and select ‘Next.’
  • Choose the destination folder where you want to save the imported files and then select ‘Finish.’
  • The EML files will be converted to MBOX format and saved in the destination folder.

It is the manual method to export PST into MBOX file format. However, for reliable and safe conversion, we recommend using Regain PST to MBOX Converter, an all in one solution to handle all kinds of issues or needs related to Outlook PST data files.

Automatic Tool to convert Outlook PST to MBOX files

This tool is specially designed with an advanced algorithm that efficiently scans and converts Outlook PST to MBOX files. Also, the software is very competent as it allows you to switch PST to MBOX, and you can transfer all of the mail data into other email clients like Spicebird, Thunderbird, etc., into MBOX format. Now, here we will show you the working procedure of this Regain PST to MBOX Converter, by following which you will be able to convert Outlook PST to MBOX file format without facing any technical issues.

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Following are the Steps to Convert PST to MBOX format:-

Regain PST to MBOX Converter tool

  • Browse and select the file that you wish to convert and click “Open”

Select Outlook PST File for Conversion

  • Now you will see the file folders. Click any folder to preview its email/item.

Show Preview of Emails before PST to MBOX Conversion

  • Now, select the destination location where you want to save the MBOX file. Click “Save Now” option to complete the process.
  • Here you can also merge your entire converted folders items in a single MBOX file, if you wish

Select the destination location to save converted MBOX file

  • Finally, you will get a notification on your screen displaying “saving” process has been complete.

Successfully Convert PST file to MBOX format


Converting PST files to MBOX format can be a challenging task, but it is essential if you want to switch from Microsoft Outlook to another email client that supports the MBOX file format. In this blog post, we have outlined two methods for converting PST files to MBOX format: using a third-party tool and using manual methods. While using a third-party tool is the easiest and most reliable method, manual methods can also be used if you don’t want to use a third-party tool. Choose the method that works best for you, and enjoy using your new email client that supports the MBOX file format.

Author: Henry Bray

Henry Bray is a young technologist and content a Content Writer at Regain Software, loves to write about MS Outlook, MS Exchange Server, Office 365, Mozilla Thunderbird and many more email applications.

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