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“View OST file content without Exchange profile or Outlook.”

Managing Director KernelApps

What is anOST file?

OST file stands for Offline Storage Table which is an offline copy of the Exchange mailbox. You can make changes in OST file content in offline mode. The changes made in OST file will get automatically updated by synchronization when connected with Exchange Server.

Where is the OST file located? OST file can be found without opening Outlook/ Exchange by 2 ways..

01 Searching at default location

You will find the OST file at this default location- C:\Users\user\AppData\Local\Microsoft\Outlook Or C:\Documents and Settings\\Local Settings\Application Data\Microsoft\Outlook

02 With Search option in OST Viewer tool

In OST Viewer tool, Search option automatically extracts all the stored OST files from the specified drive at one go.

To perform this, enter the drive location and click Search in Source File Selection dialogue box. All the OST files are extracted at once, thus making the task of locating OST file convenient for users.

OST Viewer Tool What’s it for?

Opening OST mailbox items without Exchange profile/connection

Salient Features

Know all the crucial features integrated with the tool to open and view all kinds of OST files.

Access OST Files Without Exchange Server

Access OST Files Without Exchange Server OST Viewer tool allows access to Exchange Offline folders file (OST) without establishing a connection with MS Exchange Server. The tool scans OST file and displays its entire content including emails, calendar items, notes, contacts, etc.

Find and Open Emails

Find and Open Emails With OST Viewer tool, you have the privilege to access particular email items with ‘Find’ option. In the selected mailbox folders, you filter the emails by From, To, Subject, Date Range, Attachments, etc. Thus you can locate and preview specific emails.

Saves Email List in HTML

Saves Email List in HTML The OST Viewer tool allows you to save the list of OST emails in HTML format. You can copy or print this list. The tool also provides access to email attachments in a single click.

Opens All Kinds of OST Files

Opens All Kinds of OST Files OST Reader tool is capable of opening healthy as well as corrupt OST files. The software is capable of opening OST files without connecting to an Exchange profile.

Search OST Files

Search OST Files The tool makes the task of finding OST file easier with the Search option. This option locates the OST file within the specified location. You need to enter the drive in which you know your OST file is located. The tool will automatically fetch the OST file, and you can open it by clicking on it.

Open Multiple OST Files

Open Multiple OST Files You can open as many OST files as required. There is no restriction in the number of OST files to view. You can add multiple OST files with the + button in the Source File Selection dialogue box. This feature saves the users’ time from adding individual OST files one-by-one.

Generates File Analysis Report

Generates File Analysis Report Free OST Viewer tool creates reports having details of all item types such as emails, contacts, email flow density as per sender or data, notes, etc. It helps you analyze the OST file data.

High Software Compatibility

High Software Compatibility Kernel OST Viewer Free tool extends support for all versions of MS Exchange Server (2019, 2016, 2013, 2010, 2007, 2003, 2000, 5.5, and 5.0), MS Outlook (Office 365, 2021, 2019, 2016, 2013, 2010, 2007, 2003, 2002, 2000, 98, and 97).


Kernel OST Viewer is an easy to use software that can view all your healthy or corrupted OST files in few simple steps. Let’s check them out.
  1. Run the software and click on the Browse button to select a single or multiple OST file(s) and click on Next to proceed.
  2. The system will show you the Process Information; there you need to click on the Finish button.
  3. In the next step, you need to click on the files you want to view. Select them one by one to view the content.
  4. Note: You can also generate an analysis report. For this, you need to select the type of report you want to generate from the right corner of the screen.

You can configure an Office 365 account in Outlook using IMAP configuration. Then as the rest data is saved as a copy of mailboxes in OST file, the configured Office 365 data is also copied in local OST file.
OST file, as we know is an offline copy of the mailbox available on the Exchange. To access OST file with latest information, its synchronization with Exchange is needed. When the mailbox is unavailable on Exchange Server permanently, then the OST file is termed as orphaned OST file.
Yes. You can view the attachments in the OST emails. Here are the steps:
  1. Step1: Select the folder from left pane
  2. Step2: From the right pane, select the email of the attachment you want to open
  3. Step3: In the email preview double click on the attachment.
You can use Search option in OST Viewer tool to find your OST file easily by providing the drive location.
Using the File Analysis Reports feature, you can have the overall information about the content of OST file. Let us have a look at the reports available.
  • Total item types: Generates a graph between Total item types and item count.
  • Mail flow density by date: Generates a graph between Item count and date.
  • Mail flow density by senders: Generates graph between Item count and senders.
  • Interaction between users: Generates graph between Item count against Sender & Receiver pair.

How it Works?


Software Prerequisites & Recommendations

About Software

  • Version


  • Version Support

    Windows 365/ 11/ 10/ 8.1/ 8/ 7/ Vista/ XP/ 2000/ 98/ NT/ 95

System Requirements

  • Hard Disk

    50 MB of disk space

  • Memory

    64 MB RAM (128 MB Recommended)

  • Processor

    Intel® Pentium Processor compatible (x86, x64) or equivalent

Software Guides

What customers say about Kernel OST Viewer

(4.9 / 5) 466 Reviews

This is the best option among all OST viewer software in the market. I have used it to open corrupted OST file, and it has done it very smoothly. Thanks!

Harry Ban

I am very impressed with the user-interface of this software. It is very simple and secure to open OST file. I have used it more than twice. Thanks!


This OST viewer is very effective and useful to open OST file. I have tried it several times without any cost. Highly recommended!

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