Corbett

OST to EML Converter

Corbett OST to EML Converter opens Outlook OST files on Windows and saves every email as its own EML file, in bulk or for chosen folders only. Folders, attachments and dates stay in place and Outlook does not need to be installed. Try free demo first.

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4.6 out of 5 from 683 reviews

Works offline on your PC. Corbett never sees your OST 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

Conversion scope

OST to EML Converter for Offline outlook mail on Windows

OST to EML Converter Saves Every email as its own EML file

An OST file is the local mailbox copy that Outlook retains. EML files open in Thunderbird, Apple Mail and many other clients. OST to EML converter reads Outlook OST files on Windows and saves every email as its own EML file, with your OST files left as they were.

Kept in output

Email body and headers
Attachments
Sender and receiver
Dates and subjects
Folder tree

OST input types

Offline OST files
Orphaned OST files
Single OST files
Folders of OST files

Outputs

EML
MBOX
PDF
HTML
TXT
CSV
Gmail
Office 365
IMAP

Not needed

Outlook install
Internet connection
Mailbox password
Extra software

Outlook cannot import from an OST file

Microsoft overview of Outlook Data Files says you cannot import from an OST file so a copy kept after a profile change or a server move stays locked away. An EML file holds one message and opens in many clients. OST to EML converter reads the OST on Windows and saves every email as EML, with your OST left as it was.

Import OST file into Outlook

Related pages: OST Converter, EML Converter, PST to EML Converter, OST to MBOX Converter and MBOX to EML Converter. Other mail files sit on email converter tool page.

Core features

OST to EML Converter Features by Screen

Five screens of Corbett OST to EML converter software, in conversion order.

OST to EML converter email data files list

Source files

Add Your OST Files

Select Open, then Email Data Files and add your OST files. OST to EML converter brings your mail into its panel and no Outlook is needed.

A spare PC with no Outlook still works. OST to EML converter reads your files and leaves them as they were.

Batch loading

Choose Files or Choose Folders

Select Choose Files for one OST file or a few. Select Choose Folders to load an entire directory of OST files in one step.

Loaded mail appears in one tree with a checkbox beside every item so OST to EML converter handles many OST files in a single session. No file size limit applies.

OST to EML converter email preview with content, header, properties, hex and raw views

Message preview

Preview OST Mail Before Converting

Click any message and a reading pane opens beside five analysis views. Use them to confirm correct mail before OST to EML 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.

OST to EML converter export menu with email file and document formats

Output formats

Select EML as Your Output Format

Select EML under Email Files in the Export menu. The same load exports MBOX, 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

Set EML Export Options Before You Save

Switch on open folder after export, leave out greyed out folders, create empty folders and include email headers. Every folder converts to a matching folder of EML files 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 EML output.

Working process

How to Convert OST to EML in Four Steps

Four steps take your OST files to EML. Try them on a few files in free demo first.

Add your OST files

Start OST to EML converter, select Open, then Email Data Files and add your OST files. Select Choose Files for one file or Choose Folders for many.

Preview and select mail

Your OST folders load as one tree. Click any email to preview it, tick what you need and search by keyword to trim your OST to EML conversion.

Choose EML output

Select Export, then EML under Email Files. MBOX, PDF, HTML, TXT, CSV sit in the same menu for other jobs.

Save your EML output

Set options, select Browse for a folder and press Save. Live progress shows every folder and Open Folder takes you to your EML output.

Moving the result into a client is covered in Import EML files to Outlook and Import EML to Thunderbird account.

Working process

OST to EML Converter Video Walkthrough

Prefer text? Open Import EML files to Outlook for the next move with your finished EML output.

Extra options

More OST to EML Converter Features for Big Jobs

Small options that save hours when you convert OST files in bulk with OST to EML converter.

Bulk OST input

Many OST files convert in one session

Folder hierarchy

EML output follows your OST tree

No file size limit

Any OST 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

OST to EML Converter Output Formats

OST to EML converter saves mail as EML and the same load exports more targets. Match your format to where your mail will open.

EML

One file for every message

MBOX

One file per folder for Thunderbird and Apple Mail

PST

A fresh Outlook file

PDF

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 OST to EML Converter on a Real OST File

Install free demo, load a OST file and choose EML. Free demo converts 10 emails per folder so your output is quick to check.

Download free demo

Try before you buy

Free Demo vs Full OST to EML Converter

Free demo of OST to EML converter opens, previews and searches your full OST file. Only conversion is capped.

Feature	Free demo	Full version
Open OST files and folders	Yes	Yes
Preview and search	All available	All available
Emails converted per folder	10	Unlimited
OST size and mail count	Conversion stops at 10 per folder	No limit
Price	Free	From $99 one time

Use cases

Who Needs a OST to EML Converter?

Anyone who holds OST mail that will not open where needed.

Outlook and Exchange users switching programs

OST to EML converter saves mail as EML files that Thunderbird and Apple Mail import so your mail opens in Thunderbird, Apple Mail and any client that reads EML.

IT admins

Convert a folder of OST files to EML in one batch and hand every user a ready tree.

Legal and compliance teams

Save mail with headers and attachments preserved for review and discovery.

Archive keepers

Convert OST files that only one program opens into EML that more programs read.

Anyone with orphaned OST files

Open mail from an OST file that Outlook no longer opens and save it as EML.

Selective exporters

Search by sender or subject and save only the matching emails.

Why Corbett

Why Choose Corbett OST to EML Converter?

No subscription

Lifetime price from $99

Works offline

No sign-in and no upload

Originals stay safe

OST files open read only

envelope-fill

No Outlook needed

No size limit

Any OST 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

OST to EML Converter Scope and Limits

OST to EML converter converts OST files into EML. Here is what that includes and where it stops.

Capability	Supported	What it means
File to file conversion	Yes	OST to EML, MBOX, PDF, HTML, TXT, CSV and more
Folder tree	Kept	EML output follows your OST folders
Outlook installed	Not needed	Files open on a PC with no Outlook
Source OST 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 stay in the source file
Mac and Linux	No	OST to EML converter installs on Windows only

Manual route or tool

OST to EML Converter vs Manual Route

Here is where the manual route stops and where OST to EML converter takes over.

Job	Manual route	OST to EML Converter
Cost	Free	From $99 one time
One email	Open and save by hand	Works too
EML file output	Not offered in Outlook	One EML per email
Many OST files	Slow and error prone	Folders of OST files in one session
Folder tree	Reshuffled	Same as the source
Search before export	Basic search only	Name, subject, To, From and content
Outlook installed	Required	Not needed

Global recognition

OST to EML Converter Software Users Trust

Users rate Corbett OST to EML converter 4.6 out of 5 from 683 reviews and these software directories list it.

CNET
Download.io
UpdateStar
TopSoftware Advisor
SaaSHub
Uptodown

Specifications

OST to EML Converter Specifications

Download details

Download size: 87.4 MB
Demo limit: 10 items per folder
Delivery: After payment, mail arrives with a download link and a licence key.
Licence: Personal: 5 machines. Business: 25 machines. Enterprise: 100 machines. Lifetime validity.

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System

Hard disk: 150 MB of free space
RAM: 4 GB of memory minimum
Processor: 1 GHz Intel Pentium minimum and 2.4 GHz advised
Interface: English
Input: OST files

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 OST to EML 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

OST to EML Converter Reviews

OST to EML converter shares 683 reviews on software index sites and customer feedback.

4.6 out of 5

Collected across 683 reviews from software indexes and customer feedback. Three reviews below are unedited.

Did the job really well

This OST to EML converter tool is just the right app for my needs. I had to convert my OST emails to EML format. The application did the job really well.

Anthony Shueh

Simple and quick

Great application. It was quite simple to use, and converted my files super quick, too. I will suggest everyone to give this software a try. Download the free OST to EML Converter demo version to understand the working.

James Bruce

Done in a few minutes

A colleague of mine mentioned this Corbettsoftware OST to EML file Converter tool to me. Suffice it to say, I’m glad the application worked so efficiently and converted all my Outlook OST files to EML file format within a few minutes.

Sarah Corea

Before conversion

Prepare Your OST Files for EML Conversion

Three short checks keep your OST to EML conversion clean.

Make a OST copy

Backup your OST files on a safe drive before you start. OST to EML converter opens files read only and a spare copy protects the original.

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

Every email becomes its own EML file so thousands of messages need a destination disk with free room.

Need an OST file in Outlook later? Read Import OST file into Outlook.

Best practice

How to Keep Your OST to EML Conversion Safe

A conversion only helps if your mail arrives in full. Four habits keep your data safe through it.

Backup first

Copy your original OST files before you start. Keep 3 copies on 2 types of media with 1 copy off site.

Start with one file

Convert one small OST file with OST to EML converter and open a few emails in EML. 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 OST files until counts match. Delete them only after you open converted mail.

Common questions

OST to EML Converter FAQs

OST to EML converter steps, formats, limits and licence answers.

What is an OST to EML converter?

An OST to EML converter opens Outlook OST files and saves every email as its own EML file. Corbett OST to EML Converter does that offline on Windows so OST file converter needs no Outlook.

How do I convert OST to EML?

Open OST to EML converter, select Open, then Email Data Files and add your OST file. Preview your mail, select Export, then EML under Email Files and press Save.

Can OST to EML converter open an orphaned OST file?

Yes. It reads the OST file directly so an orphaned OST or one from a deleted profile still opens. It does not need the original Exchange account or Outlook.

Can I import an OST file into Outlook?

Not directly. Microsoft says Outlook cannot import from an OST file. Convert it to EML with OST to EML converter and import the EML files instead.

Which programs open the EML files from OST to EML converter?

Thunderbird, Apple Mail and any client that reads EML open them. Outlook imports EML files too, as the Import EML files to Outlook guide shows.

Can OST to EML converter save OST mail as PST instead?

Yes. PST sits under Email Files in the same Export menu. For a PST only job, open OST to PST Converter.

Can OST to EML converter save attachments only?

Yes. A separate option saves attachments alone, with a file extension filter for specific types.

Does OST to EML converter keep email headers?

Yes. Headers stay with every EML file and the Include email headers option adds them to the output.

Can OST to EML converter convert many OST files at once?

Yes. Select Choose Folders and load a directory of OST files, then OST to EML converter converts every file in one session.

Does OST to EML converter keep my folder tree?

Yes. EML output follows the order of your source folders and the Create empty folders option preserves folders that hold no mail.

Does OST to EML converter keep attachments?

Yes. Attachments stay with every message and a separate option saves attachments alone with a file extension filter for specific types.

Can OST to EML converter convert only some emails?

Yes. Advance search filters by name, subject, To, From and content and OST to EML converter converts only matching mail.

Can OST to EML converter preview mail first?

Yes. Click any message and five views open: content, message header, properties, hex and raw message.

Can OST to EML converter send mail straight to Gmail or Office 365?

Yes. Gmail, Office 365 and IMAP sit in the Export menu. Sign in to the target account and the mail lands there.

Does OST to EML converter have a size limit?

No. OST to EML converter sets no size cap and batch mode takes many files at once. Keep free disk space for your output.

Does OST to EML converter need Outlook?

No. OST to EML converter reads OST files on its own so it works on a PC without Outlook.

Will OST to EML converter change my OST file?

No. OST to EML converter opens your files read only and output goes to a new folder.

Does my OST data pass through Corbett?

No. Conversion happens on your PC with no upload. Corbett never sees your OST files or messages.

Does OST to EML converter work on a Mac?

No. OST to EML converter installs on Windows only. Copy your OST files to a Windows PC and convert them there.

How many emails can free demo convert?

Free demo of OST to EML 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.

Which Windows versions work?

Windows 11 (64 bit), 10, 8 and 7, plus Windows Server 2016, 2012 R2 and 2008. There is no macOS or Linux build.

How many PCs can one licence activate?

Personal licence works on 5 machines for $99, Business handles 25 for $299 and Enterprise works on 100 for $499. All three are one time payments with lifetime validity, 24/7 support and a 30 day refund.

OST guides

OST to EML Converter Guides for Common Jobs

Every page below handles one OST job and answers questions it raises.

Getting into the OST

Use the EML files

Convert OST to EML Today

Test OST to EML Converter on a spare OST 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