Jagware
OST Viewer Tool

OST File Reader designed to preview emails, contacts, and calendars from corrupted, oversized, or inaccessible OST files.

(Average Rating 4.9 based on 778 Reviews)

Preview OST files from Microsoft 365, Exchange, Outlook 2021/2019/2016, etc.
Software allows you to preview all OST folders such as inbox, outbox, deleted items, sent, draft and more.
Open OST files with any encryption, such as No Encryption, High Encryption or Compressible Encryption.

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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 version, 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

Helpful Features

What Makes Jagware OST File Viewer Stand Out From Others?

Support All Types of OST File

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

View All Data from OST Files

This tool allows you to open and preview all items within 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 load multiple OST files individually, 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 attachments and allows you to preview emails and attachments 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 download the OST Viewer Tool for free on multiple desktops and laptops.

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.

Why Recommend?

What Makes Jagware OST Viewer the Top Choice?

viewing inaccessible ost files

Viewing Inaccessible OST Files

When Outlook is uninstalled or an Exchange account is inactive, Jagware Free OST Viewer allows access to orphaned, corrupted, or unrecognize OST files.

digital forensics & legal investigation

Digital Forensics & Investigation

This reliable software allows users to preview OST files with metadata, trace email communication, and analyze messages without modifying the original old OST file.

corporate email audit

Corporate Email Audit

The OST Viewer enables auditors to retrieve all email contents (including deleted items) for compliance or regulatory reviews, without needing Outlook installed or configured.

cross-version outlook support

Cross-Version Outlook Support

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

How to View OST File Using Outlook OST Viewer?

Jagware OST File Viewer is a trustworthy solution for previewing OST files and all their components, including emails, contacts, calendars, tasks, and journals. This software supports files from all Outlook versions, including Outlook 2021, 2019, 2016, 2013, and earlier. You can easily open damaged, corrupted, inaccessible, or dismounted OST files without any limitations.

Simple Steps to Read OST File:

Step 1: Download and Launch OST File Reader.
Step 2: Click on "Add File" and select the OST file you wish to preview.
Step 3: Select the specific OST mailbox folder you wish to open.
Step 4: Select the email you want to view to preview its content.

Specifications

System Requirements to Install Jagware Free OST Viewer?

Software Download

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File Size: 3 MB

Version: 2.0

Limited Version

In a free 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 2.4 GHz processor

Compatible Operating System

Microsoft Windows – Microsoft Windows: Windows 11(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.

OST Component Preview

What Data Can Be Opened Using Jagware OST File Viewer?

emails
Emails

Contacts

Appointments

tasks
Tasks

notes
Notes

Journals

Attachments

Calendars

events
Events

Metadata

Frequently Asked Questions

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 attachments are clearly marked with an icon to easily preview attachment contained emails.

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

Absolutely, In addition to emails, the viewer displays 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.

No, not in the 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 Clients

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.

Jagware OST Viewer Tool