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Free PST Converter
Convert to Any Format

Convert Outlook PST files to EML, MSG, MBOX, PST, PDF, HTML, MHT, TEXT, CSV, JSON, VCF, and ICS. Supports ANSI & Unicode PST, password-protected and corrupted files. Recover deleted emails.

11 output formatsOutlook PST supportPreserves email structureInstant conversion

Drop PST files here

or click to browse · multiple files supported

Overview

What Is PST to MBOX Conversion?

PST to MBOX conversion takes a Microsoft Outlook PST file and exports its emails into a single .mbox file. MBOX is a standard mailbox format: one file containing many messages separated by a "From " line. It is used by Mozilla Thunderbird, Apple Mail, and many other email clients. Converting PST to MBOX is the standard way to migrate from Outlook to Thunderbird or Apple Mail without using Outlook to export.

Our free PST to MBOX converter processes on your device. You drop one or more .pst files, and the tool extracts all emails (including recovered deleted items when possible), then writes them into one MBOX archive. All processing happens on your device; nothing is uploaded to any server.

Because MBOX is a single archive file, you get one .mbox output (or one per PST if you choose) instead of hundreds of separate files. Import that file into Thunderbird or Apple Mail and all messages appear in one folder. No Microsoft Outlook installation is required to run the converter — it works on Windows, Mac, and Linux on any modern platform.

Features

Features

Why use our PST to MBOX converter

Single MBOX archive

All selected emails from your PST are written into one .mbox file. MBOX is the standard mailbox format used by Thunderbird, Apple Mail, and many Unix mail clients.

Migrate to Thunderbird

Convert Outlook PST to MBOX, then import the .mbox file into Mozilla Thunderbird. All messages appear in one folder — no need to open Outlook.

Migrate to Apple Mail

Apple Mail can import MBOX files. Convert your PST to MBOX on any device, then add the file to Mail on Mac for a full migration from Outlook.

Bulk PST to MBOX

Add multiple PST files. Merge all emails into one MBOX or export each PST as its own .mbox file. Filter by date or keyword before converting.

100% private

PST is read and converted entirely on your device. Nothing is uploaded. Your Outlook data stays private.

No Outlook required

Use the converter on Windows, Mac, or Linux. No Microsoft Outlook installation or admin privileges needed.

How it works

How to Convert PST to MBOX

Four steps — no install, no Outlook, no sign-up

01
01

Open PST to MBOX Converter

This page opens with MBOX already selected as the output format.

02
02

Drop your PST file(s)

Drag and drop one or more .pst files. The tool validates the file and extracts emails, including recovered deleted items.

03
03

Browse and filter

View extracted emails in the preview. Apply date or keyword filters. All selected messages will be combined into one MBOX file.

04
04

Convert & download MBOX

Click Convert & Download. A single .mbox file is generated. Import it into Thunderbird or Apple Mail.

FAQ

Frequently Asked Questions

Common questions about PST to MBOX conversion

Q1. What is PST to MBOX conversion?
PST is Outlook's format (one file, many messages). MBOX is a plain-text mailbox format that stores many messages in one file with a standard separator. Converting PST to MBOX produces a single .mbox file that Thunderbird, Apple Mail, and other MBOX-based clients can import.
Q2. Why convert PST to MBOX?
The main reason is migrating from Microsoft Outlook to Thunderbird or Apple Mail. Both support MBOX. Converting gives you one archive file you can import without needing Outlook. MBOX is also used by Gmail Takeout and many backup tools.
Q3. Do I get one file or many?
You get one MBOX file containing all selected emails. Unlike PST to EML (one file per email), PST to MBOX produces a single archive file — the same structure Thunderbird and Apple Mail use natively.
Q4. Do you upload my PST file?
No. Conversion runs entirely on your device. Your PST is read and parsed on your device. Nothing is sent to our servers.
Q5. Do I need Outlook installed?
No. The PST to MBOX converter works on any modern platform. You don't need Microsoft Outlook to convert. You only need Thunderbird or Apple Mail (or another MBOX client) to open the resulting .mbox file.
Q6. Can I convert multiple PST files to one MBOX?
Yes. Add as many PST files as you need. You can merge all extracted emails into one MBOX file or export each PST as its own .mbox file.
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