Corbett
Corbett PST to MBOX Converter opens Outlook PST files on Windows and saves their mail as MBOX, in bulk or for chosen folders only. Folders, attachments and dates stay intact, and Outlook does not need to be installed. Try free demo first.
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Works offline on your PC. Corbett never sees your PST files or messages.
Free demo, scanned clean on VirusTotal and a 30-day money-back window.
Lifetime licence from $99 Demo converts 10 emails per folder
Quick answer
A PST to MBOX converter opens an Outlook PST file and saves its folders as MBOX files. Corbett PST to MBOX Converter does that offline on Windows, so Outlook mail opens in Thunderbird, Apple Mail and any client that imports MBOX.
What it opens
Single PST files, folders of PST files and chosen folders
What it saves
MBOX first, plus EML, PDF, HTML, TXT and CSV
Who uses it
Outlook users moving to Thunderbird or Apple Mail and admins archiving mail
Conversion scope
Teams leave Outlook for Thunderbird or Apple Mail, or archive mail in an open format. MBOX is the format those clients import and PST is not. PST to MBOX converter reads the PST on Windows and saves it as MBOX, with your PST left as it was.
Kept in MBOX
5PST input types
4Outputs
9Not carried into MBOX
4MBOX packs many emails into one file
RFC 4155 defines MBOX as many messages in one file, and Thunderbird still calls it the traditional format, as the Mozilla Thunderbird Maildir page says. A PST stays locked in Outlook, while Thunderbird and Apple Mail import MBOX. PST to MBOX converter saves every PST folder as MBOX and leaves the PST as it was.
Related pages: PST Converter, MBOX Converter, PST to EML Converter and OST to MBOX Converter. Other mail files sit on email converter tool page.
Core features
Five screens of Corbett PST to MBOX converter software, in conversion order.
Source files
Select Open, then Email Data Files, and add your PST files. PST to MBOX converter loads your mail into its panel, and no Outlook is needed.
A spare PC with no Outlook still works. PST to MBOX converter reads your files and leaves them as they were.
Batch loading
Select Choose Files for one PST file or a few. Select Choose Folders to load an entire directory of PST files in one step.
Loaded mail appears in one tree with a checkbox beside every item, so PST to MBOX converter handles many PST files in a single session. No file size limit applies.
Message preview
Click any message and a reading pane opens beside five analysis views. Use them to confirm correct mail before PST to MBOX conversion starts.
Content shows the email body. Message header lists From, To, Subject and Date. Properties reports item data, while hex and raw message views show the stored mail.
Output formats
Select MBOX under Email Files in the Export menu. The same load also exports to PST or EML for email files, and PDF, HTML, TXT or CSV for documents. Gmail, Office 365, IMAP and Thunderbird sit in the same menu for sending mail into an account.
Search by keyword first, then save only matched items. Quick search highlights hits in yellow, and Advance search checks every field or only name, subject, To, Cc and content.
Export options
Switch on open folder after export, skip greyed out folders, create empty folders and include email headers. Every PST folder converts to its own MBOX file, so your tree stays in order.
Select Browse to choose a destination, then Save. Live progress shows every folder as it converts. Need one file per message? Open PST to EML Converter.
Working process
Four steps take your PST files to MBOX. Try them on a few files in free demo first.
Add your PST files
Start PST to MBOX converter, select Open, then Email Data Files and add your PST files. Select Choose Files for one file or Choose Folders for many.
Preview and select mail
Your PST folders load as one tree. Click any email to preview it, tick what you need and search by keyword to trim your PST to MBOX conversion.
Choose MBOX output
Select Export, then MBOX under Email Files. EML, PDF, HTML, TXT and CSV sit in the same menu for other jobs.
Save your MBOX files
Set options, select Browse for a folder and press Save. Live progress shows every folder, and Open Folder takes you to your MBOX files.
Moving the result into a client is covered in Import MBOX to Thunderbird account and Import MBOX to Apple Mail account.
Working process
Prefer text? Open Import MBOX to Thunderbird account for the next move with your finished MBOX files.
Advanced options
Small options that save hours when you convert PST files in bulk with PST to MBOX converter.
Bulk PST input
Many PST files convert in one session
Folder hierarchy
MBOX files follow your PST tree
No file size limit
Any PST size and mail count converts
Five preview views
Content, header, properties, hex and raw message
Advance search
Name, subject, To, From and content fields
Quick search
Yellow hit highlights in the preview
Chosen items
Convert contacts, addresses or attachments only
Attachment extraction
Save attachments alone, any size
Email address extraction
Save addresses to their own file
Phone number extraction
Save numbers to their own file
Empty folders option
Keep the full tree, even with no mail
Cloud upload
Send mail to Gmail, Office 365 or IMAP
Output formats
PST to MBOX converter saves Outlook mail as MBOX, and the same load exports more targets. Match your format to where your mail will open.
MBOX
One file per folder for Thunderbird and Apple Mail
EML
One file for every message
PST
A fresh Outlook file
Readable pages for filing and records
HTML
Messages that open in any browser
TXT and CSV
Plain text and sheets of mail details
Gmail, Office 365 and IMAP
Mail lands in the target mailbox
Any drive
Local, USB and network folders
Free demo
Test PST to MBOX Converter on a Real PST File
Install free demo, load a PST file and choose MBOX. Free demo converts 10 emails per folder, so your output is quick to check.
Download free demoTry before you buy
Free demo of PST to MBOX converter opens, previews and searches your full PST file. Only conversion is capped.
| Feature | Free demo | Full version |
|---|---|---|
| Open PST files and folders | Yes | Yes |
| Preview and search | All available | All available |
| Emails converted per folder | 10 | Unlimited |
| PST size and mail count | Conversion stops at 10 per folder | No limit |
| Price | Free | From $99 one time |
Use cases
Anyone who holds Outlook mail that Thunderbird or Apple Mail cannot open.
Outlook users switching clients
PST to MBOX converter saves your mail as MBOX files that Thunderbird and Apple Mail import.
IT admins
Convert a folder of PST files to MBOX in one batch and hand every user a ready tree.
Archive keepers
MBOX is an open format, so PST to MBOX converter saves locked Outlook archives as files other tools read.
Cloud movers
Convert PST to MBOX first, then move mail to Gmail or Office 365.
Anyone with old PST files
Open mail from a retired PC without Outlook and save it as MBOX.
Selective exporters
Search by sender or subject and save only the matching emails.
Why Corbett
No subscription
Lifetime price from $99
Works offline
No sign-in and no upload
Originals stay safe
PST files open read only
envelope-fill
No Outlook needed
No size limit
Any PST size and mail count
Folders kept
Folders and subfolders stay in order
Smart search
Name, subject, To, From and content
30-day refund
Money-back window after purchase
Before conversion
PST to MBOX converter converts PST files into MBOX. Here is what that covers and where it stops.
| Capability | Supported | What it means |
|---|---|---|
| File to file conversion | Yes | PST to MBOX, EML, PDF, HTML, TXT and CSV |
| Folder tree | Kept | MBOX files follow your PST folders |
| Outlook installed | Not needed | Files open on a PC with no Outlook |
| Source PST files | Read only | Output goes to a new folder and your originals stay as they were |
| Internet and passwords | Not needed | Conversion works offline on local files |
| Client settings and rules | Not carried over | Account passwords, rules and saved searches stay behind |
| Password protected PST | Other tool | Remove the PST password in Outlook first |
| Mac and Linux | No | PST to MBOX converter installs on Windows only |
Outlook or tool
Outlook has no PST to MBOX export, and moving mail one email at a time is slow. Here is where the manual route stops.
| Job | Manual save | PST to MBOX Converter |
|---|---|---|
| Cost | Free | From $99 one time |
| One email | Save in a mail client | Works too |
| MBOX file output | Not offered in Outlook | Folder mail in one file |
| Many PST files | Slow and error prone | Folders of PST files in one session |
| Folder tree | Often reshuffled | Same as the source |
| Search before export | Basic Outlook search | Name, subject, To, From and content |
| Cloud upload | Not offered | Gmail, Office 365 and IMAP |
| Outlook installed | Required | Not needed |
Attachments alone come out through Extract attachments from PST file.
Global recognition
Users rate Corbett PST to MBOX converter 4.6 out of 5 from 683 reviews, and these software directories list it.
CNET
Download.io
UpdateStar
TopSoftware Advisor
SaaSHub
Uptodown
Specifications
Download details
System
Supported editions
Windows 11 (64 bit), 10, 8 and 7 in 32-bit or 64-bit, plus Windows Server 2016, 2012 R2 and 2008.
Start PST to MBOX converter with administrator rights.
Corbett has built Windows email utilities since 2020. Setup trouble and first-use questions go to our support desk.
User testimonials
PST to MBOX converter shares 683 reviews on software index sites and customer feedback.
Collected across 683 reviews from software indexes and customer feedback. Three reviews below are unedited.
I had been looking for a switch from PST to Outlook. I had been looking for ways to convert them to MBOX and keep it ready for export. Then, I came across the CorbettSoftware. It resolved all my problems and I was happy to make the right choice.
The Corbett Convert PST to MBOX is a useful tool for converting PST files without any hassles. I had tried converting multiple PST files into MBOX format. It was easy to do with just a few simple steps. In a nutshell, I would say that it is a wonderful tool.
It is an amazing tool with a fast conversion rate and easy to use interface platform. I didn't face any problem at all. I am from a non-technical background and my experience was satisfactory. Will suggest this software to all of my friends for future use.
Before conversion
Three short checks keep your PST to MBOX conversion clean.
Keep a PST backup
Close Outlook and back up your PST file on a safe drive before you start. PST to MBOX converter opens files read only, and a spare copy keeps the original safe.
Choose files or entire folders
Convert all PST files in bulk, or select folders only, which keeps your MBOX output small and focused.
Set the export options
Options cover opening the folder after export, skipping greyed out folders, creating empty folders and including email headers.
Source PST handling inside Outlook is covered in Open PST file and Import PST to Outlook.
Best practice
A conversion only helps if your mail arrives complete. Four habits keep your data safe through it.
Back up first
Copy your original PST files before you start. Keep 3 copies on 2 types of media with 1 copy off site.
Start with one file
Convert one small PST file with PST to MBOX converter and open a few emails in MBOX. Catch a wrong setting before a large job.
Check the count
Compare the message count in the folder tree with the mail in your output before you close the job.
Keep originals until checked
Store your source PST files until counts match. Delete them only after you open converted mail.
Common questions
PST to MBOX converter steps, formats, limits and licence answers.
A PST to MBOX converter opens Outlook PST files and saves their folders as MBOX files. Corbett PST to MBOX Converter does that offline on Windows, so PST file converter needs no Outlook.
Open PST to MBOX converter, select Open, then Email Data Files and add your PST file. Tick your folders, select Export, then MBOX under Email Files and press Save.
RFC 4155 defines MBOX as many messages in one file, and Thunderbird and Apple Mail import it. Open MBOX file shows how to read one.
No. Outlook has no PST to MBOX export, and moving mail one email at a time is slow. PST to MBOX converter converts entire folders in a batch.
Yes. Select Choose Folders and load a directory of PST files, then PST to MBOX converter converts every file in one session.
Yes. MBOX output follows the order of your source folders, and the Create empty folders option keeps folders that hold no mail.
Yes. Attachments stay inside every message, and a separate option saves attachments alone with a file extension filter for specific types.
Yes. Advance search filters by name, subject, To, From and content, and PST to MBOX converter converts only matching mail.
Yes. Email addresses, phone numbers, contacts and attachments save on their own.
Yes. Click any message and five views open: content, message header, properties, hex and raw message.
Import MBOX to Thunderbird account shows the steps.
Yes. Import MBOX to Apple Mail account shows the steps.
Yes. Import MBOX to Gmail shows the steps, and Gmail also sits in the Export menu for direct upload.
Yes. Import MBOX to Office 365 mail and Import MBOX to Outlook account show the steps.
No. PST to MBOX converter sets no size cap, and batch mode takes many files at once. Keep free disk space for your MBOX output.
No. PST to MBOX converter reads PST files on its own, so it works on a PC without Outlook.
No. PST to MBOX converter opens your files read only, and output goes to a new folder.
No. Conversion happens on your PC with no upload. Corbett never sees your PST files or messages.
No. PST to MBOX converter installs on Windows only. Copy your PST files to a Windows PC and convert them there.
Remove the PST password in Outlook first, then load the file.
Free demo of PST to MBOX converter opens your files, shows every folder and gives you every search and preview. Conversion stops at 10 emails per folder, enough to test your output before you buy.
Windows 11 (64 bit), 10, 8 and 7, plus Windows Server 2016, 2012 R2 and 2008. There is no macOS or Linux build.
Personal licence covers 5 machines for $99, Business covers 25 for $299 and Enterprise covers 100 for $499. All three are one time payments with lifetime validity, 24/7 support and a 30 day refund.
PST guides
Every page below covers one PST job and answers questions it raises.
Getting into the PST
Other mail files sit on email converter tool page. Account moves use Email Migration Tool or IMAP Migration Tool, broken archives belong with email recovery software and email viewer software opens mail files free. Save a live account with Office 365 Backup Tool, Outlook.com Backup Tool or Gmail Backup Tool.
Get started
Test PST to MBOX Converter on a spare PST copy first. Full access is from $99 in a single payment, and refunds are open for 30 days.
Download free demo Purchase now
87.4 MB · Windows 11 to 7 and Windows Server 2025 to 2008 · 30 day money back