How to Convert Mailbox of GNUMail to PST without Outlook?

Chirag Arora ~ Modified: January 7th, 2022 ~ Email Conversion ~ 4 Minutes Reading

Want to export all your email messages from GNUMail to Outlook? Read the article and find detailed steps with a manual guide for the conversion of GNUMail files to PST format.

About GNUMail: Primarily developed for Mac OS and Unix-like systems, GNUMail is an open-source cross-platform email client. It supports all the basic functionalities of an email application including support for IMAP and POP accounts along with local mailbox. Specific email filters are available for messages (both incoming and outgoing).
As far as the mailbox files are concerned, GNUMail stores its emails and attachments in two formats:
Maildir – A common way to organize messages in the form of subdirectories i.e., a separate file for each incoming message.
MBOX – The most common email database file format to store messages as plain text in a concatenated manner.

GNUMail to Outlook Converter

For users trying to export GNUMail emails to Outlook, the most flexible choice would be using SysTools Mac MBOX Converter. MBOX file contains both emails and attachments of GNUMail client. By converting it to PST format one can easily access it on MS Outlook. But there are various risks involved in such complex email migration, such as:

  • Corrupt attachments
  • Missing Email Headers
  • Broken links and Inline images
  • And worst of all, loss of entire emails.

What SysTools product does here is that it provides a safe means of conversion with its advanced set of algorithms. By doing so, it preserves each and every fragment of email messages with utmost accuracy and efficiency. The exported PST file is of UNICODE type which makes it 100% compatible with all latest Outlook versions including Outlook 2019, 2016, 2013 and lower. In addition, it also increases the rate of GNUMail to PST Conversion at the same time.

In case you are a Windows user and wishes to perform the migration on Windows platform, you can still do so with MBOX to PST Converter for Windows.

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Steps to Export Emails from GNUMail to Outlook on Mac OS

  1.  In the Main interface, select Add File/Folder to scan GNUMail filesadd gnumail file
  2.  Locate and Open the MBOX file(s) of GNUMail client. Click Next scan all added files
  3.  Here, select file format as Outlook PST and choose to maintain folder hierarchyselect outlook pst
  4.  Now, tap the Advance Settings button and select PST options as per requirement. A Date filter tab is also present to aid in selective emails conversion from GNUMail to Outlookadvance settings
  5.  Once the settings are saved, Change the save file location as per choicechange location
  6.  Finally click the Export button to start GNUMail files to PST conversionexport button
  7.  After completion, click Ok on the confirmation dialog box that appears on the screenconfirm gnumail to pst completion
  8.  Clicking on View Report will open the location where a detailed progress report of conversion is saved along with the exported PST of process

Users can import or open this output file on all editions of Microsoft Outlook without fail and do with it whatever desired.


GNUMail is a stable and feature-rich email utility but is witnessing minimum activity in development in recent times. Thus users are switching towards other email applications and MS Outlook is one of them. But migration scenarios such as this are quite complex and risk-oriented. That is why this article introduces an efficient tool that specializes in GNUMail to Outlook PST migration. Implement the defined steps and let go of all your concerns regarding GNUMail conversion.

Common Questions & Answers

GnuMail saves mailbox data in which file formats?

GnuMail uses the maildir and MBOX file format to save its emails and attachments.

How do I export GnuMail data to Outlook 2016?

Follow the steps given in this article to easily export GnuMail emails in Outlook 2019, 2016,and lower versions.

Can I move GnuMail data to other platforms like Thunderbird?

Yes, all the email client that supports MBOX files have a direct-indirect way of importing GnuMail MBOX files as well. You can also use the given solution to transfer your GnuMail emails into EML, PST, MSG, NSF and HTML format. And later, access them in supported email clients.

Does the solution support selective or bulk conversion?

The given approach has a way of doing both selective and bulk conversion. Choose your preferred way as per requirements.