How to Export Outlook PST Emails for Free Using pstconv.jar (No Trial, No Limits)

Step-by-Step Guide: Exporting PST Emails using pstconv.jar (Free & Open Source)

This detailed guide will walk you through the entire process of extracting emails from a PST file using pstconv.jar — a fully free, open-source Java tool that converts PST files to EML (or MBOX/XML). This process is ideal for backing up Outlook emails, freeing up webmail space, or migrating to another mail client like Thunderbird.

Requirements

• Java 8 (JRE or JDK)

• pstconv.jar tool (latest version)

• PST file exported from Microsoft Outlook

Step 1: Download pstconv.jar

1. Open the GitHub repository: https://github.com/cjmach/pstconv
2. Scroll down to the Releases or Packages section.
3. Download the file named 'pstconv-0.9.9.jar'.

Step 2: Install Java 8

pstconv.jar requires Java 8 to run. Even if you have a newer Java version, Java 8 is the most stable with this tool.
Recommended download: Azul Zulu OpenJDK 8
Visit: https://www.azul.com/downloads/zulu/zulu-windows/
After installation, check with the following command in Command Prompt:

java -version

Expected output:
java version "1.8.0_xx"

Step 3: Prepare Your Files and Folders

1. Copy your PST file to a short path, e.g., C:\PST_Backup\archive.pst
2. Create an empty output folder, e.g., C:\PST_Backup\converted_emails

Step 4: Run pstconv.jar via Command Line

1. Open Command Prompt (Win + R, then type cmd and press Enter)
2. Run the following command (adjust paths as needed):

java -jar "C:\path\to\pstconv-0.9.9.jar" -i "C:\PST_Backup\archive.pst" -o "C:\PST_Backup\converted_emails" -f eml

This command tells Java to:
• Use pstconv.jar
• Input the archive.pst file
• Output emails in EML format into the converted_emails folder

Step 5: Check Your Exported Emails

Open the folder you used as output. You'll see:
• Folders matching your Outlook structure
• Emails in EML format (openable in Thunderbird, Outlook Express, etc.)
• Attachments are preserved in the EMLs

Notes & Troubleshooting

• If the PST is corrupted, run scanpst.exe (Microsoft Inbox Repair Tool).

• You can also export to MBOX or XML using -f mbox or -f xml

• This tool does not modify your PST; it only reads from it.