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How to Open OST File – Access Outlook OST Data with Ease

Written By Kristian Wilson
Marco Devin
Approved By Marco Devin  
Published On November 3rd, 2023

If users want to open an OST file then keep reading this blog till the end. Here we will cover the steps to read the OST file without damaging your data. Furthermore, we will explain how to read OST files with reliable solutions.

If you are a Microsoft Outlook user, you have probably come across the term “OST file”. These offline storage table files play a crucial role in Outlook. They allow you to work with your emails, contacts, and calendars even when you are offline. However, there may be situations where you need to access the contents of an OST file to open an OST file on another computer. And that’s where this guide comes in handy.

What is an OST File?

An OST file, short for Offline Storage Table, is a data file used by Microsoft Outlook to store a copy of your mailbox information. It allows its users to work with your emails, contacts, and calendar events even when they’re not connected to the internet. OST files ensure that you can access your data seamlessly, whether you’re online or offline.

Why Need to Open an Outlook OST File?

We all know that Outlook stores its data in two common file types OST and PST. When you configure an Exchange account, IMAP, Office 365, or email account in Microsoft Outlook, an Outlook OST file is generated. This file establishes a connection with a specific Outlook profile and is automatically encrypted using the MAPIEntryID GUID key.

However, if the user profile is deleted or the mailbox is disabled on the server, the OST file linked to that profile transforms into an orphan, rendering it inaccessible. Consequently, you cannot open, import, or access it directly within any other Outlook profile or account.

And if you set up Outlook with POP, then a PST file is created.

There are various reasons to read Outlook OST files, a few common reasons are mentioned below.

  1. If users have an orphaned OST file on the PC and the users want to open the data available in the OST file.
  2. An OST file is shared by an application or someone else, and your has not installed MS Outlook and configured it on the server.
  3. When the account was unintentionally deleted or the exchange server.

To open OST files in Outlook, you can also read the complete blog on importing OST files in Outlook. After all, the methods are quite similar.

Location of OST Files

  • OST file in Windows XP of Outlook 2000/2003/2007: – C:\Documents and Settings\%username%\Local Settings\Application Data\Microsoft\Outlook\
  • OST file in Windows Vista/7/8 of Outlook 2007: – C:\Users\%username%\AppData\Local\Microsoft\Outlook\
  • OST file location in Windows Vista/7/8/10/11 of Outlook 2010/2013/2016/2019/2021: – C:\Users\%username%\Documents\Outlook Files

Also Read:- Open Outlook in Safe mode

How to Read OST Files in Outlook

If your OST file is connected with MS Outlook, and you want to open an OST file with another Outlook profile then you need to convert OST to PST format. Follow the two steps mentioned below:

Step 1: Export the OST file from the Outlook Account

  1. Open an Outlook account.
  2. Then, click on the “File” tab and choose the “Open & Export” > “Import/Export” option.

    read ost file

  3. Now select the “Export to a File” option and click on the “Next” icon to continue.

    how to open an ost file

  4. After that, choose the “Outlook Data File (.pst)” option and Next to continue the process.

    how to open ost file

  5. Now select the folders, that you want to export.

    open an ost file

  6. Then, select the location and hit the “Finish” icon to open the OST file in Outlook.

    open outlook ost file

Now your data will save in PST format, which can easily open in any Outlook version.

Step 2: How to Open the OST file

  1. Open an Outlook account.
  2. Then, click on the “File” tab.
  3. After that, choose the “Open Outlook Data File” option.
  4. Finally, select the file exported in Step 1 and done.

With this. you can successfully open OST files in Outlook 2021, 2019, 2016, 2013, 2010 & 2007.

Still Unable to Open the OST File Do This

If you are still facing problems while opening Outlook OST files, then maybe your OST file is damaged or corrupted. In this situation, you can take the help of an expert solution named as OST Viewer Tool. This tool allows users to preview OST emails with attachments & associated items. With the help of this application, users can scan and browse corrupt or orphan OST files by using advanced scan mode.

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The best part of this software it supports reading the attachments associated with OST data directly from this software panel. Users can read different kinds of attachments like photos, documents, and files via the tool.

Working Steps to  Read Outlook OST File

Follow the below steps to read the OST file without any need for an exchange server:

1. Step: Launch the Outlook OST reader Tool open ost file outlook
2. Step: Now, Browse the OST file with the advanced scan option how to open ost
3. Step: Open the OST File Message in the Normal View Tab open ost files
4. Step: Horizontal or vertical mode to read Outlook OST files with attachments how to open ost file in outlook


In this guide, we’ve explored the significance of OST files in Microsoft Outlook and discussed why you might need to open them. Whether you choose to use Outlook directly or opt for professional software, understanding how to open an OST file empowers you to access your data when you need it the most. So, go ahead, explore your OST files, and make the most of your Outlook experience.

Remember to keep your OST files safe and consider creating backups to prevent any data loss. With the right knowledge and tools, you’ll have no trouble opening OST files effectively.

FAQ’s – Three Different Scenarios to Open OST Files

Query 1: Hey, yesterday I was checking the laptop of my ex-employee to collect office data. I have some OST files on it and I want to read them, but I don’t know the methods. If you know how to open an OST file then please let me know the process.

So, if your OST file is not connected with Outlook, then you have to help of an expert solution which is mentioned in the above post, and also convert OST to PST format. Because there are no manual methods available to open orphan OST files.

Query 2: An OST file is connected to my Outlook, but I want to open the OST file in my new Outlook account and after that, I want the data in an accessible format, so that I can read the data easily. But I don’t know the methods, could you please suggest to me the right method?

Yes, after following the mentioned steps above, you will get PST format which can easily open in any version of Outlook, you can convert PST to PDF file, which is very easy to open on any device.

Query 3: I have an old OST file on my computer but do not use Outlook anymore. Is there a way for me to read OST files in email clients other than Outlook; such as Thunderbird which I am using currently?

OST files are primarily designed for use with Outlook. To use them in other email clients, it is necessary to convert them into the supported format. For example, Thunderbird uses MBOX format, so you must first convert OST to MBOX to open an orphan OST file in that email client.