A PST and OST viewer
Browse the folder tree and preview mail, contacts, calendar, tasks and attachments safely, then search everything with full-text search.
SetuFlow PST & OST Converter
Open any PST or OST file — no Outlook required
Read Outlook data files on any Windows PC and convert them to MBOX, EML, MSG, PDF, Word, Excel and more. Handles ANSI and Unicode PSTs, offline OST files, password-protected PSTs and archives of 50 GB and beyond, with memory use that stays flat however large the file.
- Windows 10 & 11
- Free edition — 25 items per job
- Works offline
- Source never modified
Every format it converts to
Only formats that have passed our validation tests are listed. More are added as they pass.
Mailbox
MBOXEMLMSGMaildir
Documents
PDFDOCXRTFHTMLXHTMLTXTMarkdown
Data
CSVTSVXLSXJSONXML
Contacts & calendar
vCard (VCF)ICS
Packaged
ZIPTGZFolder tree
Built for the job, not the demo
14 filter criteria
Combine dates, people, subject, attachments, size, folders and more with AND/OR logic, and save the filter for next time.
Built for very large files
A 50 GB PST opens in about 20 milliseconds and converts with steady memory use — no loading the whole file into RAM.
Password-protected PSTs
Enter the PST password and the converter verifies it and opens the file. Encrypted (“High” encryption) PSTs are read too.
Pause, resume, retry
Batch queue with checkpoints: pause a job, resume it later, retry failed items, and never get duplicates.
Damaged files handled
Damaged parts of a file are skipped and listed in the report instead of stopping the job, so you still get everything readable.
What people use PST & OST Converter for
Open an OST file without Outlook
When the Exchange account is gone, its OST file still holds the mail. Copy the OST off the old PC, open it in SetuFlow, and read or export everything inside it.
PST to MBOX and Thunderbird
Convert Outlook mail to MBOX for Thunderbird, Apple Mail and other clients, ticking exactly which folders to take with you.
PST to PDF and Word
Turn an entire mailbox — or just the emails matching a filter — into PDF or DOCX documents for legal review, audits or a client handover.
Export Outlook data to Excel or CSV
Export message fields, contacts or calendar entries to XLSX, CSV, JSON or XML for reporting, analysis or loading into another system.
Three steps
- 1
Open the PST or OST
Add one file or several; protected PSTs ask for their password.
- 2
Tick folders and set filters
Pick the folders, formats and naming you want.
- 3
Export
Run it in the queue and get a report of everything exported.
Benchmarks
50 GB
PST read in under 5 minutes
13,500/s
Messages exported to MBOX
≈20 ms
To open a PST
0
Mismatches across 276 format test runs
Measured on Windows 11 with a 24-thread CPU and NVMe SSD, using test PST files from 5 to 50 GB and 200,000 messages. Every exported item in the format tests was re-read and compared by an independent checker. Your speed depends on your hardware.
Start free. Pay once you need more.
Try every feature on your own files with the Free edition. Prices in US dollars, per licence, before any applicable tax.
Free
Open, read and try every feature on real files.
Free
- Viewer with no limit
- Convert up to 25 items per job
- Every output format except MSG
- Filters, previews and job reports
Most popular
Professional
For one person converting their own mailbox.
$20.30
- No item limit
- MSG export
- Batch queue and advanced filters
- Attachment extraction
Business
For IT teams and migration projects.
Quote
- Everything in Professional
- Upload straight to an IMAP mail server
- Advanced job reports for audit
- More parallel workers for large jobs
- Mailbox analysis report
System requirements
- Operating system
- Windows 10 or 11, 64-bit
- Microsoft Outlook
- Not required — the converter reads the file itself
- Other software
- None — the installer includes the runtime
- Install
- Per-user install, no administrator rights needed
- OST in use
- Close Outlook or copy the OST first — a file locked by Outlook cannot be read
- Command line
- Included, for scripted and scheduled jobs
PST & OST Converter, answered
What people want to know before they buy. Anything else — the assistant or a human will answer it.
Yes. SetuFlow reads OST files directly, including the compressed OST format used by Outlook 2013 and later. If Outlook is still running with that profile, close it or copy the OST somewhere else first.
Yes, if you know the password: the converter asks for it, checks it and opens the file. It does not bypass or recover forgotten passwords.
It has been tested with PST files up to 50 GB. It streams the file instead of loading it into memory, so memory use stays roughly flat as files get larger.
Not yet. PST output is in final testing and will be added to this page when it has passed validation in Outlook. Today you can export OST and PST mail to MBOX, EML, MSG, PDF and the other formats listed above.
It reads around damaged areas and exports everything that is still readable, listing what it had to skip. It does not recover deleted items.
The Free edition is free forever, with a limit of 25 items per conversion job. Professional removes the limit. Your licence key is checked offline on your own PC, so the converter keeps working without an internet connection and nothing about your mail is ever sent to us.
No. The converter is desktop software: it reads the file on your disk and writes the result to a folder you choose. Your source file is opened read-only and never changed. The only time data leaves the PC is if you choose to upload to your own mail server in the Business edition.
More SetuFlow data tools
Try PST & OST Converter free on your own files
Download the Free edition, open your files and convert 25 items per job. Upgrade when you are sure it does what you need.
Professional licence $20.30 · Windows 10 and 11 · No Outlook required