How to Convert PST to EML Files Without Losing Data

Written By Loic Traves
Approved By Mithilesh Tata
Updated on June 11th, 2026
Reading Time: 5 minutes

“I have several PST files from my old Outlook setup, and I need to convert them to EML format so I can access the emails in Thunderbird. Some of these PST files go back five years and contain important client communication that I cannot afford to lose. What is the most reliable way to convert PST to EML without any data loss or formatting issues?”

– Valentina Torres, Spain

PST files are native to Microsoft Outlook. They present accessibility issues when companies migrate to alternative email platforms. PST to EML Conversion works across Thunderbird, Apple Mail, and more environments. This blog covers both the manual approach and the professional ConverterTools PST to EML Converter Tool. Key focus areas include folder hierarchy, metadata retention, and attachment integrity. Enterprise users can complete the conversion with full data accuracy and zero loss.

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What are PST and EML Files?

Features	PST	EML
Developed By	Microsoft	Open Standard (MIME)
Format Type	Proprietary	Open
Storage Structure	Single file for entire mailbox	One file per email message
Stores	Emails, contacts, calendars, tasks	Individual email messages
Platform Dependency	Platform dependent	Platform independent
Supported By	Microsoft Outlook only	Thunderbird, Apple Mail, and more
Best Used For	Outlook local backup and archiving	Cross-platform email access and migration

Why Convert Outlook PST to EML Files

Each email is stored as an individual file, making management easier.
It preserves email properties, attachments, & metadata.
Useful for email archiving and long-term storage.
Makes email migration to other platforms more convenient.
Reduces dependency on Microsoft Outlook for email access.
Enables quick access to individual messages without loading a large mailbox.
Supports better organization and backup of important emails.

User-Driven Method to Convert PST to EML Format

Mozilla Thunderbird is a free, open-source email client that supports EML format natively. This serves as a practical option to convert the PST files to EML. The steps below walk through the complete conversion process:

Manual Step Guide to Save Outlook PST Emails as EML

Install Microsoft Outlook and Mozilla Thunderbird on your system.
Further, open Thunderbird and go to Tools >> Import.
Select Mail >> click Next.
You have to choose Outlook as the source email application.
Complete the import process >> wait for Outlook mailbox data to appear in Thunderbird.
Open the imported folder >> select the emails you want to export.
Right-click the selected emails >> choose Save As.
Browse to the desired destination folder.
Thunderbird saves each selected email in EML format.

Limitations

Cannot directly open standalone PST files in most Thunderbird versions.
Time-consuming for large PST files.
Bulk conversion options are limited.
Folder hierarchy may require manual verification after export.
Not suitable for enterprise-scale PST to EML conversion.

Enterprise-Ready Infrastructure to Convert PST to EML

Enterprises managing large PST data across multiple mailboxes need a more dependable approach. The ConverterTools PST to EML Converter handles the complete conversion from a single interface. It processes emails, contacts, calendars, tasks, and metadata accurately. Multiple PST files can be processed in one operation. This saves considerable time and effort on large-scale enterprise migration projects. Additionally, this tool can convert PST to PDF and other file formats.

Steps to Convert PST File to EML

Download the PST to EML Converter Software.

Add PST files or folders and click the Next button.

Afterwards, preview and select files and press Next.

Furthermore, choose the EML as the destination format.

Lastly, apply filters, set the location, and click Start Export.

Real Case Study

A legal firm in Chicago was switching its entire email setup from Outlook to Thunderbird. The IT team had 60 PST files on hand, each belonging to a different user, with the total data sitting at around 480 GB. On top of that, the compliance team had a specific requirement. They only wanted emails from January 2021 through December 2023 in the final output.

The team started with the manual Thunderbird approach on a test mailbox. One mailbox alone took over six hours and several attachments were missing from the output. That result made it clear a different approach was needed.

They brought in the ConverterTools PST to EML Converter, added all 60 PST files in a single batch, and set the date range before starting. The entire job finished in under eight hours. Every attachment, folder, and email came through exactly as expected. Later, with the same software, they import PST Files to Office 365 without any extra effort.

Conclusion

This conversion gives organizations the flexibility to access PST files across multiple platforms. The manual method through Thunderbird serves well for small-scale requirements, but the professional utility handles tasks in bulk in a single go. It retains full metadata and folder hierarchy, and delivers accurate EML output ready for enterprise use. Organizations managing legacy PST data or planning a platform migration will find the professional tool a reliable and time-efficient solution to convert PST to EML file format.

Frequently Asked Questions

Q1: Can I convert Outlook PST to EML files without Outlook?

Ans: Yes, the ConverterTools PST to EML Converter can process PST files directly without requiring Outlook installation, making the conversion faster and more convenient.

Q2: What are the benefits of converting PST to EML?

Ans: Converting PST to EML allows emails to be accessed in multiple email clients such as Thunderbird, Apple Mail, and Windows Mail. It also stores each email as a separate file, simplifies email sharing, and preserves attachments and metadata.

Q3: What should I do if my PST file is corrupted?

Ans: If your PST file is corrupted, you can first try Microsoft’s Inbox Repair Tool (SCANPST.exe). If the issue persists, the ConverterTools PST to EML Converter can help process accessible mailbox data and export it to EML format.

Q4: Why are some PST emails not appearing after conversion?

Ans: Missing emails can occur due to PST corruption, incomplete imports, filtering settings, or unsupported mailbox items. Before conversion, verify the PST file integrity and ensure all folders are selected.

Q5: Is there a file size limit for converting PST files to EML?

Ans: File size limitations depend on the conversion method being used. Manual approaches may struggle with very large PST files and can become slow or unstable. The ConverterTools PST to EML Converter is designed to handle large PST files and multiple mailboxes in a single operation.

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About The Author:

Loic Traves

Loic Traves is a seasoned technical expert who has helped thousands of clients with Microsoft Outlook and various cloud-based email platforms. He enjoys writing about email client backups and migration processes. Passionate about supporting users in need, he strives to provide the latest insights, clear explanations, and practical, user-friendly solutions.