Best GainTools OST Viewer Alternatives ranked by AI · updated Aug 2026

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A Windows utility for previewing Outlook OST mailbox files and their folders, messages, attachments, contacts, and calendar data. It serves users who need an inexpensive way to inspect OST contents independently of an Outlook profile.

Developer: GainTools Price: Free viewer; paid export features available 🎯 gaintools.com/ost-viewer

💻 Windows Email Recovery data recovery ost viewer

Top 6 GainTools OST Viewer alternatives

OSTFile.co.uk File Viewer

OSTFile.co.uk

An online utility for opening and inspecting Outlook OST files without configuring a full Outlook profile. It is aimed at users who...

Pros

Works through a web browser rather than requiring Outlook installation
Useful for quickly inspecting mailbox contents
Supports common OST mailbox data categories

Cons

Uploading mailbox data may create privacy and compliance concerns
Online processing can be impractical for large OST files
Typically offers fewer export and recovery controls than desktop tools

Free

Alternatives to OSTFile.co.uk File... → Visit site

SysTools OST Viewer

SysTools OST Viewer is a free tool to open, view, and read OST files without Outlook. It helps users to preview the...

Free

Alternatives to SysTools OST Viewe... → Visit site

Kernel for OST Viewer

Kernel for OST Viewer is a free tool to open and view OST files with an easy-to-use interface.

Pros

Simple and intuitive UI
Supports large OST files

Cons

Does not allow OST file conversion

Free

Alternatives to Kernel for OST Vie... →

BitRecover OST Viewer

BitRecover OST Viewer is a free tool to open and view OST files with a focus on data integrity and accuracy.

Pros

Focus on data integrity
Lightweight and fast

Cons

Lacks advanced features for file analysis

Free

Alternatives to BitRecover OST Vie... →

Stellar Viewer for OST

Stellar

A Windows application that scans and previews the contents of Outlook OST files, including messages, attachments, contacts, calendars, and tasks. It targets...

Pros

Strong preview support for complex mailbox folders and attachments
Can help inspect inaccessible or orphaned OST files
More recovery-oriented than basic online viewers

Cons

Full export and repair capabilities require a paid upgrade
Heavier installation than OSTFile.co.uk
Windows-only workflow

Free viewer; paid recovery and export features available

Alternatives to Stellar Viewer for... → Visit site

Aryson OST Viewer

Aryson Technologies

A Windows-based application for viewing and analyzing Outlook OST files without requiring the original Exchange connection. It lets users browse common mailbox...

Pros

Supports browsing messages, contacts, calendars, and attachments
Local processing is preferable for confidential mailbox data
Useful for technicians handling multiple OST investigations

Cons

Advanced functions require a license
Less convenient than a browser tool for one-off viewing
Windows-only

Free viewer; paid export features available

Alternatives to Aryson OST Viewer → Visit site

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