OST to MBOX Converter

Convert Outlook files to Thunderbird MBOX files.

  • Maintains the original folder structure after the conversion.
  • Convert PST and OST files to MBOX
  • Microsoft Outlook installation is not required.
OST to MBOX Converter

OST Converter - Outlook to Thunderbird Migration

Maintains On-Disk Folder Structure

Option to retain the original Outlook file folder structure after conversion to mbox files.

100% Safe and secure migration

Microsoft Outlook installation is not required. Convert OST to MBOX including emails, contacts, calendars, tasks, notes. etc.

Maintain all email data, such as:

Subject, send and receive dates, sender and recipient addresses, HTML markup, attachments and images, Internet headers.

No limitation on file size

No limitation on the file size and number of PST and OST files to be exported.

Compatible with all Outlook versions

Export Outlook 2019, 2016, 2013, 2010 emails to Thunderbird MBOX files.

1-Click Email Converter

Convert .pst to .mbox and .ost to .mbox in single click. The program generates report for the data conversion process.

Software Specification

Deploy and manage OST to MBOX Converter across your company, no IT expertise required.

System Requirements

Hard Disk Space

100 MB of available disk space


1 GB RAM (32-bit); 2 GB RAM (64-bit)


1 GHz or faster processor

Operating System

Windows 11, 10, 8.1, 8, 7, Vista, XP
Windows Server 2016/2012/2008 R2/2008/2003 R2/2003

Supported Versions

Microsoft Outlook 2021/2019/2016/2013/2010/2007/2003

Software Download

This download contains portable version of OST to MBOX Converter.

Setup Command-Line Options EULA

Software Delivery

All products are delivered electronically through online digital download or automated email.

Upgrade Policy

Free upgrades for one year from date of purchase.

Additional requirements

See Also

Convert Outlook data files to Thunderbird (MBOX)

The normal Thunderbird import process requires that you have a compatible version of Outlook installed on your computer. If you do not have Outlook installed, there are alternatives as noted below.