Corbett
Corbett OST to PST Converter opens Outlook OST files on Windows and saves a PST file that Outlook opens, 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 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
Quick answer
An OST to PST converter opens Outlook OST files and saves a PST file that Outlook opens. Corbett OST to PST Converter does that offline on Windows, so your mail opens in Outlook.
What it opens
Offline OST files, Orphaned OST files, Single OST files
What it saves
PST first, plus EML, MBOX, PDF, HTML
Who uses it
Outlook and Exchange users and admins moving or archiving mail
Conversion scope
An OST file is the local mailbox copy that Outlook keeps. PST is the file Outlook imports and opens. OST to PST converter reads Outlook OST files on Windows and saves a PST file that Outlook opens, with your OST files left as they were.
Kept in output
5OST input types
4Outputs
10Not needed
4Outlook cannot import from an OST file
Microsoft overview of Outlook Data Files says you cannot import from an OST file, so mail in an orphaned or offline OST stays locked away. A PST file is the Outlook data file you can import and open. OST to PST converter reads the OST on Windows and saves a PST, with your OST left as it was.
Related pages: OST Converter, PST Converter, OST to EML Converter, MBOX to PST Converter and OLM to PST Converter. Other mail files sit on email converter tool page.
Core features
Five screens of Corbett OST to PST converter software, in conversion order.
Source files
Select Open, then Email Data Files, and add your OST files. OST to PST converter loads your mail into its panel, and no Outlook is needed.
A spare PC with no Outlook still works. OST to PST converter reads your files and leaves them as they were.
Batch loading
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 PST converter handles many OST 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 OST to PST 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 PST under Email Files in the Export menu. The same load also exports EML, MBOX, PDF 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. For PST output, create an individual PST file for every folder, so every PST stays small and easy to open.
Select Browse to choose a destination, then Save. Live progress shows every folder as it converts, and Open Folder takes you to your PST output.
Working process
Four steps take your OST files to PST. Try them on a few files in free demo first.
Add your OST files
Start OST to PST 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 PST conversion.
Choose PST output
Select Export, then PST under Email Files. EML, MBOX, PDF, HTML, TXT sit in the same menu for other jobs.
Save your PST output
Set options, select Browse for a folder and press Save. Live progress shows every folder, and Open Folder takes you to your PST output.
Moving the result into Outlook is covered in Import PST to Outlook and Open PST file.
Working process
Prefer text? Open Import PST to Outlook for the next move with your finished PST output.
Advanced options
Small options that save hours when you convert OST files in bulk with OST to PST converter.
Bulk OST input
Many OST files convert in one session
Folder hierarchy
PST 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 PST converter saves mail as PST, and the same load exports more targets. Match your format to where your mail will open.
PST
A file Outlook opens, with one file per folder as an option
EML
One file for every message
MBOX
One file per folder for Thunderbird and Apple Mail
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 PST Converter on a Real OST File
Install free demo, load a OST file and choose PST. Free demo converts 10 emails per folder, so your output is quick to check.
Download free demoTry before you buy
Free demo of OST to PST 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
Anyone who holds OST mail that will not open where needed.
Outlook and Exchange users switching programs
OST to PST converter saves mail as a PST file that opens in Outlook, so your mail opens in Outlook.
IT admins
Convert a folder of OST files to PST 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 OST files that only one program opens into PST that more programs read.
Anyone with orphaned OST files
Open mail from an OST file that Outlook no longer opens and save it as PST.
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
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 PST converter converts OST files into PST. Here is what that covers and where it stops.
| Capability | Supported | What it means |
|---|---|---|
| File to file conversion | Yes | OST to PST, EML, MBOX, PDF, HTML, TXT and more |
| Folder tree | Kept | PST 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 may stay in the source file |
| Mac and Linux | No | OST to PST converter installs on Windows only |
Manual route or tool
Here is where the manual route stops, and where OST to PST converter takes over.
| Job | Manual route | OST to PST Converter |
|---|---|---|
| Cost | Free | From $99 one time |
| One email | Open and save by hand | Works too |
| PST file output | Not offered in Outlook | Full PST file |
| Many OST files | Slow and error prone | Folders of OST 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 installed | Often required | Not needed |
Global recognition
Users rate Corbett OST to PST 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 OST to PST 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 PST 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 am really happy with this offline OST to PST converter tool. I had to convert multiple OST files into PST format. After scourging the internet for while, I came upon this application. Suffice it to say, I’m satisfied with the tool.
This software has a pretty simple UI that made by conversion much easier than I though I would be. And boy its quite fast, too. Exported all my 300 OST files under a couple of minutes. Easy to use GUI will help home users as well.
I used this Best OST to PST Converter application upon the suggestion of a colleague. So far it has been working fine. I would recommend all anyone to go with this app if they have to convert offline OST file to PST file format. Free demo version helps to understand features.
Before conversion
Three short checks keep your OST to PST conversion clean.
Make a OST copy
Back up your OST files on a safe drive before you start. OST to PST 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
PST output needs free room on the destination disk, and one PST for every folder keeps files small.
Seeing an Outlook error on the file? Read Outlook data file usage is disabled on this computer.
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 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 PST converter and open a few emails in PST. 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 PST converter steps, formats, limits and licence answers.
An OST to PST converter opens Outlook OST files and saves a PST file that Outlook opens. Corbett OST to PST Converter does that offline on Windows, so OST file converter needs no Outlook.
Open OST to PST converter, select Open, then Email Data Files and add your OST file. Preview your mail, select Export, then PST under Email Files and press Save.
Yes. It reads the OST file directly, so an orphaned OST or one from a deleted profile still loads. It does not need the original Exchange account or Outlook.
Not directly. Microsoft says Outlook cannot import from an OST file. Convert it to PST with OST to PST converter and import the PST instead.
Yes. Choose the individual PST option and every OST folder saves as its own PST, so files stay small and easy to open.
Yes. Search by name, subject, From, To, Cc or date range, tick the mail you need and save only those emails to PST.
Yes. EML and MBOX sit under Email Files in the same Export menu, next to PST.
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 OST files, then OST to PST converter converts every file in one session.
Yes. PST 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 OST to PST 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. OST to PST converter sets no size cap, and batch mode takes many files at once. Keep free disk space for your output.
No. OST to PST converter reads OST files on its own, so it works on a PC without Outlook.
No. OST to PST 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 OST files or messages.
No. OST to PST converter installs on Windows only. Copy your OST files to a Windows PC and convert them there.
Free demo of OST to PST 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.
OST guides
Every page below covers one OST job and answers questions it raises.
Use the PST files
Fix Outlook errors
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 OST to PST 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