Corbett

OST to MBOX Converter

Corbett OST to MBOX Converter moves Outlook OST mail into MBOX files that Thunderbird, Apple Mail and other clients import. Single or bulk jobs keep the folder structure, attachments and message order intact. Filters limit the output to the mail required, and the trial edition allows testing first.

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4.6 out of 5 from 393 reviews

The OST file never leaves this PC. Corbett receives nothing.

Free demo, scanned clean on VirusTotal and a 30-day money-back window.

Lifetime licence from $99 Demo converts 10 items

MBOX facts

OST to MBOX Converter for Thunderbird and Apple Mail

Outlook stores mail in OST files that no mail client outside Outlook opens. MBOX keeps every message of a folder in one file that Thunderbird, Apple Mail and Postbox accept. OST to MBOX Converter bridges the two without touching the source.

Inside the MBOX file

Email bodies
Attachments
Sender and receiver
Subject lines
Dates and times
Folder structure
Read and unread flags

OST file sources

Offline OST files
Orphaned OST files
Single OST files
Batches of OST files
Complete folders
Several folders at once
Emails, contacts and attachments

More outputs

MBOX (main output)
PST
EML
PDF
vCard
CSV, TXT and HTML
Contacts alone
Email addresses alone

Not in MBOX

Calendars
Tasks
Notes
Journals

Why Move Mail to MBOX

Mac users run Apple Mail and many Windows users run Thunderbird, and neither opens an OST file. After the export to MBOX, either client imports the mail folder by folder from a local disk.

Open MBOX file

Core features

Four Moves From OST to MBOX

Install, load OST files or folders, set filters, then export as MBOX.

Install

Get the Software

Launch the downloaded setup on Windows. Once the software opens, add OST files to the main window.

Free demo available
Windows 10, 8 and 7
Small footprint
No other program needed

OST folder tree with selection checkboxes

Folder selection

Select OST Files and Folders

Add single files or entire folders. The preview lists the contents in source order before the export starts.

Items listed by folder
Source order kept
Preview before export
Several folders at once

Message preview

Review Mail Before It Converts

A preview shows an email in full, which lets admins confirm the data ahead of the MBOX output.

Content shows the email body
Message Header lists From, To and Subject
Properties reports item attributes
Hex View and Raw Message show stored values and code

Selective backup

Apply Filters to the MBOX Output

Limit the export with date, To, From, subject, email address and contact filters so only the needed mail reaches the MBOX file.

Date filter
To and From filter
Subject filter
Address filter
Contact filter
Attachment filter

Output options

Select MBOX and Click Export

Choose MBOX as the format, set a local destination and click Export. The software then saves MBOX files folder by folder.

MBOX files placed on a local drive
Attachments kept with the mail
Need PST files? See the OST to PST Converter
Want EML files? Try the OST to EML Converter for that job

Before converting

Preparation for OST to MBOX

Three quick steps prevent trouble later.

Source file

Find the OST

Track the OST down in the Outlook data directory and back it up before starting.

Item scope

Full mailbox or filters

Send every folder through in one run, or apply filters when only part of the mailbox must reach the MBOX file.

Target client

Know where the mail goes

Thunderbird imports MBOX through an add-on, while Apple Mail has a built-in import. Decide the target client before the run.

Opening the converted file is covered in Import MBOX to Apple Mail account and Import MBOX to Thunderbird account.

Free demo

Free Trial of the OST to MBOX Converter

Demo mode handles 10 messages or folders. Import the sample MBOX file into a mail client before buying.

Download free demo

Before purchase

Manual Steps Against OST to MBOX Converter

Outlook has no MBOX option for an OST file, and no built-in step reaches Thunderbird. The table sets the manual path against the tool.

Task	Manual route	Tool
Cost	Free	$99 one time
One email	Save in a mail client	Works too
MBOX file output	Missing from Outlook	Folder mail in one file
Bulk jobs	One item at a time	Batches in one run
Folder hierarchy	Often reshuffled	Same as the source
Attachments	Saved apart from mail	Stay with the email
Filters	Mail search only	Date, To, From, Subject, Address
Other formats	Not available	PST, EML, PDF, CSV, HTML

The green row is the only job possible by hand.

Email addresses alone come out with Extract email addresses from OST file .

Specifications

OST to MBOX Converter Requirements

Download details

Version: 3.0
Download size: 47.6 MB
Demo limit: 10 items
Delivery: Electronic: download link and licence key by email
Licence: Personal: 2 PCs. Business: 10 PCs. Enterprise: unlimited PCs.

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System

Hard disk: 100 MB free space
RAM: 512 MB or more, 1 GB preferred
Processor: 1 GHz CPU, faster at 2.4 GHz
Interface: English
Input: Outlook OST files

Supported editions

Windows 10 in 32-bit or 64-bit, plus Windows 8.1, 8, 7 and all lower versions.

Start with Run as Administrator.

Corbett has built Windows email utilities since 2020. Early problems and setup questions reach the support team.

Working process

OST to MBOX Converter in Action

Prefer text? The Open MBOX file post covers what to do with the finished MBOX.

Common questions

OST to MBOX Converter FAQs

Steps, data loss and Thunderbird.

How do I convert my OST files to MBOX with the app?

Download and install the software, then select the OST files and folders to convert. Choose any advanced filters, select the MBOX format and click Export.

Can data be lost during conversion?

No. The tool is designed so that no data is lost during or after the conversion.

Can the exported file open in Mozilla Thunderbird?

Yes. Convert the OST files to MBOX and then import them into the Thunderbird client.

Can several folders convert together?

Yes. Batch jobs cover single files, folders and multiple folders in one go.

Does the demo have limits?

Yes. The trial converts 10 messages or folders, enough to check the MBOX output.

Are attachments exported with the mail?

Yes. Attachments go into the MBOX file with their emails, or they can be extracted separately.

Does the folder hierarchy stay in place?

Yes. The structure of the OST file is the structure of the output.

Can only selected items convert?

Yes. Filters on To and From, date, subject, email address and contacts limit the export.

Which other formats are possible?

The same tool outputs PST, EML, PDF, CSV, HTML, vCard and text.

Which versions of Windows work?

Windows 10 in 32-bit and 64-bit, plus lower versions such as 8.1, 8 and 7.

How much memory and disk space is needed?

RAM begins at 512 MB, 1 GB is preferred, and the drive needs 100 MB free.

Which processor does it need?

A 1 GHz processor runs it, and 2.4 GHz is the recommended speed.

What licences exist?

The Personal licence covers 2 PCs or laptops, Business covers 10 and Enterprise has no PC limit.

How does the download reach the buyer?

By electronic delivery once payment is complete.

Can the money be refunded?

Yes. A refund can be requested within 30 days of buying.

Step by step

Help With MBOX Mail

Posts on opening, importing and mining MBOX mail.

Opening MBOX mail

Send the mail on

Import MBOX to iCloud Mail

Mining the data

Moves between hosted accounts use the Email Migration Tool . Server cutovers use the IMAP Migration Tool. Further formats are covered in the email converter tool. Broken archives belong with the email recovery software. The mail file viewer is part of the email viewer software. Same family: OST to PDF Converter and OST Converter Software. Also see the MBOX Converter, MBOX to PST Converter, MBOX to EML Converter, MBOX to PDF Converter and Thunderbird Backup Tool.

User testimonials

OST to MBOX Converter Reviews

393 ratings from users who pushed OST mail into MBOX with Corbett.

4.6 out of 5

Collected across 393 reviews collected from portals and email, left unedited.

Moved Outlook mail to Apple Mail

Really great software. I had to move my Outlook mails to Mac OS supported Apple mails. For that, I had to convert OST emails to MBOX format. This app helped get my work done.

Nick Larsson

Simple and fast

What I liked about this software was its simple UI and fast speed. Didn’t faced any trouble with using the tool, and moreover, it exported my OST files to MBOX format pretty quickly, too.

Sam Mitchell

Big job done swiftly

I was quite concerned as I had to export a lot of OST files to MBOX format in a short amount of time. Luckily, I found this OST to MBOX Converter tool, and it really helped getting done with my work swiftly.

Tom Price

Get started

Send Offline Outlook Mail to MBOX Now

Test the trial on a spare copy, then import the MBOX into a client. Buying costs $99 one time, and the refund period is 30 days.

Download free demo Purchase now

47.6 MB · Windows 10 and below · 30 days money back