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4n6 Software
OST File Viewer

Forensically Tested OST Viewer Free Download to Open and View OST Files in Easy Steps

Software Rating (Average Rating 4.9 Based on 1455 Reviews)

  • Open OST Files of Microsoft Outlook, Exchange / IMAP configured Account
  • Supports to View & Open Outlook data files: PST , BAK, NST, & ZDB File
  • Use the Advance Search feature to selectively open and read OST files
  • View OST Files Content, Properties, Header, Raw Message, and Hex View
  • Open OST files on Windows 11, Windows 10, Windows 8.1, and below editions
  • Automatically detects the Default OST Location of Configured Outlook Profile
  • Browse suspected OST file from any location & perform deep scan
  • OST File Viewer offers Compact View to find evidences in folders/sub folders
  • Search suspected evidences / messages by keyword with inbuilt Search
  • OST Forensics Viewer Analyze OST files with Details without Outlook app

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professional ost viewer

Best OST Viewer Tool Software

Tried and Tested OST File Viewer Software

The 4n6 OST Viewer Software is a highly professional application developed for quick evaluation of OST files. The tool is simple to use, user-friendly, secure, and totally self-contained. It provides two ways for browsing and selecting OST files. To simply pick and browse OST files, you may either choose from a folder or open a specified Outlook data file.

  • 100% tested and risk-free OST File Viewer
  • For both personal and business users
  • Comes up with the very simple user interface
multi-functional ost file viewer

A Multi-Functional OST File Viewer Software

The OST File Viewer, in addition to being a simple OST reader, also functions as an email forensics tool. It allows you to study OST files in a variety of settings for in-depth scanning of the OST files. In addition to the standard content mode, you may read OST files in headers, raw, and hex modes. As an added feature, it allows you to quickly search for a certain item in your OST file.

  • Download OST File Viewer on Windows Computer
  • Install the app properly and click the Open button
  • Browse OST files / folders into the software panel
  • Click on loaded files and preview the complete details

Main Features

Main Features of OST File Viewer for Digital Evidences

Open Offline Outlook Data Files

Open Offline Outlook Data Files

Using OST Viewer Tool, Investigators can easily open & read evidences from OST File. This OST Reader Utility will help investigators to view Messages from MS Outlook, Office 365 / MS Exchange OST (which holds the replica of data present in Exchange Mailbox / Office 365) or any IMAP configured OST files. Hence, the name Outlook Offline Storage Table.

Apart from OST, it can help to view data of other Outlook Data files, PST, OST, BAK, NST, and ZDB. This OST File Reader supports to gives a preview of all messages along with attachments, contacts, calendars, tasks & journals. Free OST Viewer software not lets you to view emails but also supports to save attachments of respective emails. You just have to right-click on the attachment and choose the option needed. This amazing OST File Opener software comes up with so many features. With this app, one can easily view unlimited OST files in easy steps.

Deep Scan of Outlook OST Files

Deep Scan of Outlook OST Files

OST File Viewer Tool provides the preview of OST data file in 5 different Modes:

  • Content: View OST File email with Header & Body Content along with attachments just like you view.
  • Properties: Displays properties like Subject, Date & Time, Sent & Received Name & Address, Address Type, Transport Message Headers, Internet Headers, etc
  • Header: Displays Key element properties like From, To, Subject, Date, MIME-Version, Content-Type, Message-ID etc.
  • Hex: Shows the email information in hexadecimal which can help investigators to investigate bit by bit information for example any hidden information, altered data and more.
  • Raw Message: Displays header information (Received: from, Message-ID:, From, To, Date, Subject, Mime, and Content Type etc).
2 Editions of 4n6 OST Viewer Tool

2 Editions of 4n6 OST Viewer Tool

This Free Forensics OST File Viewer software is available in 2 different versions for the ease of evidence for investigations:

  • Portable Version [For Investigators]: It is an executable file i.e (click & Run). There is no need to install OST File Reader on your machine. It can be launched directly via USB / flash drive or any removable file.
  • Installer Version [For Normal Users]: OST File Viewer installs the application files onto the system along with shortcut and uninstaller.
Read OST file with or without Outlook

Read OST file with or without Outlook

The OST file opener is provided with two inbuilt option to browse OST Files:

  • Open Configured Outlook Data Files: The forensic OST File viewer software is featured with an advanced option to auto- detect the OST file. It automatically detects the Outlook files (OST, PST, NST) associated/ configured with the MS Outlook Profile
  • Choose from a Folder: Using this option of OST Reader Tool, one can browse Outlook data files (OST, PST, NST, BAK, ZDB) from any location.
Quick & Advance Search Facilities

Quick & Advance Search of OST Viewer

Search facility can be a crucial feature for investigators while examining an OST filea as it holds a large amount of critical data. In most cases, OST is large sized holding thousands of emails, and it can be difficult to manually check every mail. With the search facility you can find evidences by entering keywords like email address, date, or any information that you want to filter out from rest of the messages. This feature can be applied on Emails, Calendars, Contacts, Tasks, Notes, etc.

Compact View of Forensic OST Viewer

Compact View of Forensic OST Viewer

During the forensics investigation, finding evidences from multiple email folder is one of the most difficult task faced by the investigators. To solve this issue the OST file viewer software offers an advanced compact view option. Enabling or disabling this feature, permits users to view all the folders & sub-folders within the OST file. Also, it is the best OST reader by which one can easily view unlimited OST files in some easy steps. So, free download this OST file opener tool.

Maintain Accuracy of OST Files
Maintain Accuracy of OST Files

4n6 Free OST File Viewer Software is the perfect solution for all your needs. The software always maintains the folder hierarchy and data integrity of the OST file while opening it. There is no harm to the OST file contents. We guarantee that this proven software will provide you with the accurate and exact previews. So, free download OST Viewer on your Windows computer and read OST files without Outlook application.

No Limitations on OST File Size
No Limitations on OST File Size

We are happy to inform you that 4n6 OST file viewer software has no file size limit. This advanced software allows you to easily open and view Outlook PST files of any size without any problem. You can easily preview large OST files within moments. Additionally, the OST Evidences Viewer has a very basic graphical user interface for the ease. No technical support is required to read OST file without Outlook using 4n6 software.

Open and Read OST Files in Batch
Open and Read OST Files in Batch

4n6 OST Viewer tool has many advanced features and unique features that make it better than other tools. One such feature is the batch open feature. This advanced feature allows you to easily browse and view multiple Outlook OST files in batch at the same time. Now you don't have to keep running the application and opening PST files one by one. With this application, you can easily save your precious time and open unlimited OST files with just simple clicks.

View and Save OST File Attachments
View and Save OST File Attachments

The 4n6 OST File Reader Software for Windows allows you to easily open and view attachments included in each Outlook OST file. When you right-click on an OST file attachment, the OST Viewer Tool provides three options: Open, Save, and Save All. This amazing feature allows you to easily open and save OST attachments. To save all the attachments of OST email at once, select the Save All option.

Software Specifications

OST Viewer Software Specifications

Software Download

Size : 5.0 MB

Version : 4.2

System Specifications

Hard Disk Space
100 MB of free hard disk space

Minimum 512 MB RAM

Intel® Core™ 2 Duo CPU E4600 @ 2.40GHz 2.39GHz Processor

Supported Editions

  • Microsoft Windows – Windows OS 11 (64 bit), 10, 8, 7 (32 bit or 64 bit) & Windows Server 2019, 2016, 2012 R2, 2008

Software Screenshots

Step by Step Working Process of OST File Viewer
download ost viewer tool
browse ost file
Preview content of ost file
preview header of ost files
preview hex values of ost files


Video Tutorial to Help View OST Files

User Reviews & Industry Recognitions

Awards & Reviews
CNET Reviews and Award

According to Cnet, the 4n6 OST Data Viewer is the top choice for safeguarding your files security consistently. This software allows you to access numerous OST files without needing to install Outlook.

SOftware Informer Reviews and Award

According to Software Informer, the OST File Viewer developed by the reputable company 4n6 is considered the top choice for individuals, organizations, and especially forensic investigators. The application has received a perfect 5-star rating from various platforms.


Comparision of Free & Pro Version


Free Viewer

Viewer Pro

View OST File Content

Auto File Scanning

View OST Attachments

Advance Search Option

Export Unlimited Emails



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Frequently Asked Questions

Follow these simple steps to open & view OST File email data:

  • Step 1: Download & Run Forensic OST Viewer Tool on Windows Machine
  • Step 2: Click on Open & select auto-locate/ manual option to upload emails.
  • Step 3: Select folder & preview Email messages within the OST file.
  • Step 4: Go to the search option & apply filters to find specific emails

Yes, OST File Viewer Tool provides the complete preview of email headers along with Properties View which provides details of CLIENTSUBMITTIME, MESSAGEDELIVERYTIME & CREATIONTIME.

Yes, it is possible with this portable OST File Viewer software. The Portable version of this software does not require the installation of Outlook to view or open OST files.

The tool provides advance search options. Using the search functionality, you can easily filter OST emails sent by a particular person, email address, date / time or any other known keyword.

No, there are no file size limitation imposed on the tool. You can check an unlimited number of OST files.


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