Corbett
Corbett OLM to MBOX Converter opens Outlook for Mac OLM files on Windows and saves every folder as an MBOX file, in bulk or for chosen folders only. Folders, attachments and dates stay intact, and Outlook for Mac does not need to be installed. Try free demo first.
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Works offline on your PC. Corbett never sees your OLM 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
An OLM to MBOX converter opens Outlook for Mac OLM files and saves every folder as an MBOX file. Corbett OLM to MBOX Converter does that offline on Windows, so your mail opens in Thunderbird, Apple Mail and any client that imports MBOX.
What it opens
Single OLM files, Folders of OLM files, Outlook for Mac archives
What it saves
MBOX first, plus EML, PDF, HTML, TXT
Who uses it
Outlook for Mac users and admins moving or archiving mail
Conversion scope
An OLM file is the archive that Outlook for Mac exports. MBOX files import into Thunderbird and Apple Mail. OLM to MBOX converter reads Outlook for Mac OLM files on Windows and saves every folder as an MBOX file, with your OLM files left as they were.
Kept in output
5OLM input types
4Outputs
9Not needed
4The OLM archive is the only export Outlook for Mac offers
Microsoft guide to exporting Outlook for Mac items to an archive file says an OLM archive is the only export option, and that support for legacy Outlook for Mac ends in October 2026. MBOX is the format RFC 4155 defines for many messages in one file, and Thunderbird and Apple Mail import it. OLM to MBOX converter saves your OLM mail as MBOX and leaves the OLM as it was.
Related pages: OLM Converter, MBOX Converter, OLM to PST Converter, OLM to PDF Converter and MBOX to PST Converter. Other mail files sit on email converter tool page.
Core features
Five screens of Corbett OLM to MBOX converter software, in conversion order.
Source files
Select Open, then Email Data Files, and add your OLM files. OLM to MBOX converter loads your mail into its panel, and no Outlook for Mac is needed.
A spare PC with no Outlook for Mac still works. OLM to MBOX converter reads your files and leaves them as they were.
Batch loading
Select Choose Files for one OLM file or a few. Select Choose Folders to load an entire directory of OLM files in one step.
Loaded mail appears in one tree with a checkbox beside every item, so OLM to MBOX converter handles many OLM 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 OLM 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 EML, PDF, HTML and more, and the menu lists Gmail, Office 365, IMAP and Thunderbird 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 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, and Open Folder takes you to your MBOX output.
Working process
Four steps take your OLM files to MBOX. Try them on a few files in free demo first.
Add your OLM files
Start OLM to MBOX converter, select Open, then Email Data Files and add your OLM files. Select Choose Files for one file or Choose Folders for many.
Preview and select mail
Your OLM folders load as one tree. Click any email to preview it, tick what you need and search by keyword to trim your OLM to MBOX conversion.
Choose MBOX output
Select Export, then MBOX under Email Files. EML, PDF, HTML, TXT, CSV sit in the same menu for other jobs.
Save your MBOX output
Set options, select Browse for a folder and press Save. Live progress shows every folder, and Open Folder takes you to your MBOX output.
Moving the result into a client is covered in Import MBOX to Thunderbird account and Import MBOX to Gmail.
Working process
Prefer text? Open Import MBOX to Thunderbird account for the next move with your finished MBOX output.
Advanced options
Small options that save hours when you convert OLM files in bulk with OLM to MBOX converter.
Bulk OLM input
Many OLM files convert in one session
Folder hierarchy
MBOX output follows your OLM tree
No file size limit
Any OLM 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
Empty folders option
Keep the full tree, even with no mail
Cloud upload
Send mail to Gmail, Office 365 or IMAP
USB and NAS targets
Save output to external drives and network storage
Output formats
OLM to MBOX converter saves 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 OLM to MBOX Converter on a Real OLM File
Install free demo, load a OLM 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 OLM to MBOX converter opens, previews and searches your full OLM file. Only conversion is capped.
| Feature | Free demo | Full version |
|---|---|---|
| Open OLM files and folders | Yes | Yes |
| Preview and search | All available | All available |
| Emails converted per folder | 10 | Unlimited |
| OLM size and mail count | Conversion stops at 10 per folder | No limit |
| Price | Free | From $99 one time |
Use cases
Anyone who holds OLM mail that will not open where needed.
Outlook for Mac users switching programs
OLM to MBOX converter saves mail as MBOX files that Thunderbird and Apple Mail import, so your mail opens in Thunderbird, Apple Mail and any client that imports MBOX.
IT admins
Convert a folder of OLM files to MBOX in one batch and hand every user a ready tree.
Legal and compliance teams
Save mail with headers and attachments intact for review and discovery.
Archive keepers
Convert OLM files that only one program opens into MBOX that more programs read.
Anyone with old OLM archives
Open a Mac archive on a Windows PC 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
OLM files open read only
envelope-fill
No Outlook for Mac needed
No size limit
Any OLM 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
OLM to MBOX converter converts OLM files into MBOX. Here is what that covers and where it stops.
| Capability | Supported | What it means |
|---|---|---|
| File to file conversion | Yes | OLM to MBOX, EML, PDF, HTML, TXT, CSV and more |
| Folder tree | Kept | MBOX output follows your OLM folders |
| Outlook for Mac installed | Not needed | Files open on a PC with no Outlook for Mac |
| Source OLM 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 |
| Calendars, tasks and notes | Check output | Mail is the focus, so other item types may stay in the source file |
| Mac and Linux | No | OLM to MBOX converter installs on Windows only |
Manual route or tool
Here is where the manual route stops, and where OLM to MBOX converter takes over.
| Job | Manual route | OLM to MBOX Converter |
|---|---|---|
| Cost | Free | From $99 one time |
| One email | Open and save by hand | Works too |
| MBOX file output | Not offered in Outlook | Folder mail in one file |
| Many OLM files | Slow and error prone | Folders of OLM files in one session |
| Folder tree | Often reshuffled | Same as the source |
| Search before export | Basic search only | Name, subject, To, From and content |
| Outlook for Mac installed | Often required | Not needed |
Global recognition
Users rate Corbett OLM to MBOX converter 4.6 out of 5 from 683 reviews, and these software directories list it.
CNET
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TopSoftware Advisor
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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 OLM 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
OLM 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 to convert OLM Files and Folder to Convert into MBOX format. The aim is to shift the mails to Gmail application. I came across the OLM to MBOX Converter, and so, I used it. I am quite satisfied with its functionalities and have recommended it to my colleagues, too.
I wanted to export my OLM emails into MBOX format. I was looking for software which could fix my problem. Here, I used the Corbett Software OLM to MBOX Converter and it resolved my problem just in few simple steps. I am very happy with the software.
I am fully satisfied with the Corbett software as it has a simple user interface. It is a quick, reliable and easy to handle application. I didn't face any problems and found it suitable for a non-technical user like me.
Before conversion
Three short checks keep your OLM to MBOX conversion clean.
Make a OLM copy
Back up your OLM files on a safe drive before you start. OLM to MBOX converter opens files read only, and a spare copy keeps the original safe.
Choose all mail or chosen items
Convert every folder at once, or limit the job to the folders and items you need.
Leave space for output
MBOX files hold many emails apiece, so a large mailbox needs a destination disk with free room.
Moving mail to Gmail? Read Import OLM to Gmail accounts.
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 OLM files before you start. Keep 3 copies on 2 types of media with 1 copy off site.
Start with one file
Convert one small OLM file with OLM 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 OLM files until counts match. Delete them only after you open converted mail.
Common questions
OLM to MBOX converter steps, formats, limits and licence answers.
An OLM to MBOX converter opens Outlook for Mac OLM files and saves every folder as an MBOX file. Corbett OLM to MBOX Converter does that offline on Windows, so OLM file converter needs no Outlook for Mac.
Open OLM to MBOX converter, select Open, then Email Data Files and add your OLM file. Preview your mail, select Export, then MBOX under Email Files and press Save.
Yes. Load the OLM archive and OLM to MBOX converter reads it on Windows, with no Mac and no Outlook for Mac needed.
Not directly. Thunderbird imports MBOX, not OLM. Convert the OLM with OLM to MBOX converter and import the MBOX files instead.
Yes. Convert to MBOX and import into Gmail, or use Gmail in the Export menu to upload the mail straight to your account.
Yes. PST and EML sit under Email Files in the same Export menu, next to MBOX.
Yes. A separate option saves attachments alone, with a file extension filter for specific types.
Yes. Headers stay with every message, and the Include email headers option adds them to the output.
Yes. Select Choose Folders and load a directory of OLM files, then OLM 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 with 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 OLM to MBOX converter converts only matching mail.
Yes. Click any message and five views open: content, message header, properties, hex and raw message.
Yes. Gmail, Office 365 and IMAP sit in the Export menu. Sign in to the target account and the mail lands there.
No. OLM to MBOX converter sets no size cap, and batch mode takes many files at once. Keep free disk space for your output.
No. OLM to MBOX converter reads OLM files on its own, so it works on a PC without Outlook for Mac.
No. OLM 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 OLM files or messages.
No. OLM to MBOX converter installs on Windows only. Copy your OLM files to a Windows PC and convert them there.
Free demo of OLM 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.
OLM guides
Every page below covers one OLM job and answers questions it raises.
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 OLM to MBOX Converter on a spare OLM 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