Jagware
OST Viewer Tool

Download OST File Reader to preview OST files with emails, contacts, and calendars without worrying about corrupted, oversized, or inaccessible OST files, and without requiring Outlook installation.

(Average Rating 4.9 based on 778 Reviews)

Read all OST items all OST components including emails, contacts, calendar and other data.
Preview OST files from Microsoft 365, Exchange, Outlook 2021/2019/2016, etc.
Software allows to preview all OST folders such as inbox, outbox, deleted items, sent, draft and more.
The tool offers a serial feature to count numbers of emails that helps to easily locate any specific emails.
OST File Viewer offers to open an OST file without Outlook or any other application.
Allows to preview damaged, corrupted, inaccessible, OST cannot accessed or oversize OST files.
Open OST file in all encryption such as No Encryption, High Encryption or Compressible Encryption.
Allows to add multiple OST files one by one for easily examine.
This software indicate attachment contained email and Preview attachments separately.
Free OST Viewer supports all version of Mac and Windows Operating system.

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VirusTotal Safety Score: 100%

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30-Days Money Back Guarantee*

Download Now
VirusTotal Safety Score: 100%

Upgrade Now
30‑day Money‑Back Guarantee*

Demo Edition: In the free trial, you can preview OST content (emails, contacts, calendars, attachments). Upgrade to convert OST files to PST, PDF, EML, MBOX and more.

Screenshot Video

Video

Software Guide eula

Eula

What Makes Jagware OST File Viewer Stand Out From Others?

Notable Attributes of Free OST Viewer

Support All Types of OST File

This software allows to preview corrupt OST files, inaccessible, and oversize OST files without making any recovery process.

View All OST File Data

This tool allows you to open and preview everything from an OST file such as emails, contacts, calendars, tasks, journals and more.

Compatible with All OST File Versions

You can open OST files from Microsoft 365, Exchange Server, and all Outlook versions, including Outlook 2021, 2019, 2016, 2013, and earlier.

Add and Manage Multiple OST Files

You can add and open multiple OST files one at a time, making it easy to browse and examine their contents.

Built for Digital Forensics & Investigation

Designed with forensic use in mind, this software lets you view both ANSI and UNICODE OST files and gives access to all data required for legal or investigation purposes.

Attachment Identification & Preview

Easily identify emails that contain attachments. The software highlights attachment and allows to preview emails and attachment separately.

Highlight Emails with Attachments

Emails that include attachments are marked with a special star icon, making them easy to spot and preview without altering the original file.

Displays Full Email Metadata

View all important metadata such as From, To, CC, Subject, and more — helping you understand each message in detail.

Email Sorting for Efficient Review

Use built-in sort options to arrange emails by serial, subject, or attachments so you can quickly find specific messages — ideal for professionals and corporate users.

Standalone Application – No Dependencies

This is a standalone tool — you don’t need to have Outlook, Exchange Server, Microsoft 365, or even Outlook for Mac installed.

Free for Multi-System Use

You can freely download OST Viewer Tool on multiple desktop and laptops without making any investment.

Upgrade Option: Convert OST Files to 35+ Formats

Upgrade anytime to convert OST files into PST, PDF, and 35+ other formats. The upgraded version also includes smart filters and can auto-detect OST files from the default system location.

What Makes Jagware OST Viewer the Top Choice?

Let's Know Why Recommend Jagware Free OST Viewer?

Viewing Inaccessible OST Files

When Outlook is uninstalled or an Exchange account is inactive, Jagware Free OST Viewer allows access to orphaned, corrupted or not recognize OST files.

Digital Forensics & Legal Investigation

This software is completely reliable for forensic experts as it allows users to preview an OST file with metadata, trace email communication and analyze messages without modifying the original old OST file.

Corporate Email Audit

When reviewing an employee’s email history for compliance or regulatory purposes, the OST Viewer enables auditors to retrieve all email contents (even deleted items) without needing Outlook installed or configured.

Cross-Version Outlook Support

It allows open OST files created by any Outlook, Exchange Server or Microsoft 365 version as it is compatible with both ASCII or UNICODE OST files.

How to View OST File Using Outlook OST Viewer?

Jagware OST File Viewer is the most trustworthy solution to preview an OST file with all components such as emails, contacts, calendars, tasks, journals and all other OST data. This software can preview all version of any Outlook version such as Outlook 2021, 2-19, 2016, 2013, 2016 and all earlier version. You can easily open damaged, corrupted, inaccessible or dismounted OST file without facing any limitations.

Simple Steps to Read OST File:

Step 1: Download and open Free OST Viewer on your system.
Step 2: Click on Add file and select OST file as you want to preview.
Step 3: Choose the OST mailbox folder as you want to open.
Step 4: Now, Select email as you wish to read.

Jagware Free OST Viewer - Specification

What Required to Install Jagware Free OST Viewer?

Software Download

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File Size: 3 MB

Version: 2.0

Limited Version

In a trial version, you can only preview OST content and after upgrading you can convert the OST file and get 35+ Saving options.

System Specifications

Hard Disk Space
Minimum 5 MB Storage Needed

RAM
Minimum 4 GB RAM Required

Processor
Intel® Pentium 1 GHz processor (2.4 GHz is recommended)

Compatible Operating System

Microsoft Windows – Microsoft Windows: Windows 11(32 and 64 bit), Windows 10(32 and 64 bit), Windows 8.1(32 and 64 bit), Windows 8(32 and 64 bit), Windows 7(32 and 64 bit).
Mac OS: macOS 15 Sequoia, macOS 14 Sonoma, macOS 13 Ventura, macOS 12 Monterey, macOS 11 Big Sur and all older versions.

Product Guides

Electronic Delivery

After successful payment, you will receive an email with download url and activation key to upgrade into pro edition with all amazing features.

What Component Preview Using OST File Reader?

What Data Can Be Opened Using Jagware OST File Viewer?

Emails
Emails

Contacts

Appointments

Tasks
Tasks

Notes
Notes

Journals

Attachments

Calendars

Events
Events

Metadata

Often Inquired Questions Using Jagware Free OST Viewer

Mostly Asked Questions about OST File Reader

No, Jagware OST Viewer is an independent application. It doesn’t require Outlook, Exchange Server, Microsoft 365, installation to view OST files.

Yes, software displays emails along with attachments. Emails containing attachment are clearly marked with an icon to easily preview attachment contained emails.

Yes, Jagware OST File Reader support OST file created by any Outlook version including Outlook 2021, 2019, 2016, 2013 and all older versions.

Absolutely, In addition to emails, the viewer display emails, contacts, calendars, tasks, journals and notes stored in OST file.

Yes Jagware OST File Viewer is completely free and installable on multiple machines.

Yes, the tool is designed to support forensic investigation by providing access to metadata,email headers and unaltered OST content. It works with both ANSI or UNICODE OST files.

Not a free version, You can upgrade it to convert OST to PDF, PST, EML, MBOX and 35+ saving options.

Yes, Jagware OST File Reader works in both Windows and Mac OS Version, including latest version of Windows 11 and macOS 15 Sequoia.

Know our Happy Client What Says about OST File Viewer

Let’s Know What User Said After Using Jagware Free OST Viewer

Michael R.

United States

"I had an orphaned OST file" from a deactivated Outlook account, and Jagware opened it instantly. The interface is clean, and I could view all my emails and attachments without any setup. Lifesaver!

Sophie L.

United Kingdom

As someone in IT support, I often deal with user mailbox issues. Jagware’s free OST Viewer lets me quickly check contents without Outlook installed. It’s a reliable tool I now recommend to colleagues.

Carlos M.

Spain

I used Jagware OST Viewer during a client audit. I appreciated how easy it was to view email metadata and attachments. It made forensic review faster and more organized.

Emily W.

Canada

I needed a way to access my Outlook data from an old backup. Jagware worked perfectly and showed all emails, contacts, and calendar entries — even with no Outlook on my Mac.