How to Convert OST to PST [Manually]

While both OST and PST files perform specific functions, sometimes users face a deadlock when it comes to OST files. They cannot access their mailbox information in the case of non-availability of Exchange Server. And Exchange can face downtime, crash, or other technical issues at any instance. In such an event, converting the OST to PST remains the only viable option. But the process to convert OST to PST manually is a challenging task that involves multiple steps. So how can the users achieve OST to PST conversion, easily?

Offline Storage Table or OST plays an important role in saving Microsoft Exchange mailbox data in an offline folder. It helps the users to work in offline mode when there is no Internet connection, limited connectivity, or Exchange unavailability.

It simply represents a local cache of Microsoft Exchange account and syncs all the changes automatically to the Exchange server, as soon as you are connected to the Internet. Personal Storage Table or PST stores all the email data like emails, notes, contacts, tasks, calendar, etc. of the users in a local system. It is used for the actual storage and not cache storage. It keeps the emails in the same hierarchy as the main Inbox and is quite flexible.

When both OST and PST files have their distinct roles and functionalities, why do users feel the need to convert OST to PST manually? Let us find out.

Why Is OST To PST Conversion Needed?

Some of the main reasons why users need to convert OST to PST include:

  • Exchange server crash: If due to any reason Microsoft Exchange Server crashes or there is a system failure or a virus attack, you will not be able to connect to the Exchange server. These kinds of situations can impact your work/business, and your Outlook profile might not work properly. Therefore, by converting OST to PST, you can avoid such a situation.
  • Accidental deletion of Exchange Server account: If your Exchange Server account gets accidentally deleted or there is any data loss, it can be easily recovered by converting OST file to PST format.
  • Data Migration: You can easily migrate data from one machine to another by converting OST to PST. This is helpful in organizations where they are planning to shift their data between machines.
  • Exchange server maintenance: When there is an outage due to the maintenance of Exchange Server, it is crucial to still have access to all the mailbox items. This is necessary because the downtime can be long enough and your business can get impacted. Therefore, converting OST to PST is a good idea in such cases.
  • Rebuild OST file: Suppose you want to rebuild your OST file but it has unsaved data present in the OST file. In that case, you need to convert OST to PST.

Now that we know the need for OST to PST conversion, let us see how to convert OST to PST.

Quick Solution: If you wish a speedy & fast OST to PST conversion process, then go ahead with Stellar Converter for OST. Supports Office 365 & all versions of MS Outlook.

Three Methods For Convert OST To PST Manually 

Import and Export mailbox as PST file

Note: For this method to work, you must be connected to the Exchange server and have Outlook installed on your computer or laptop.

  1. First, you need to open Microsoft Outlook and click the “File Menu” present at the top left corner of Outlook.
  2. Now select “Open and Export” option from the list.
  3. There you will see 4 options. You need to click the “Import/Export” option.
  4. A new dialogue box will open up asking you to “Choose an action to perform”. Click on “Export to a file” and then click on the “Next” button to continue.
  5. On the next screen, you will be asked to select the file type to import. Choose “Outlook Data file (.pst)” and click on “Next” button to continue.
  6. Now choose the folder to export from. Here you need to select the files to be exported and click on the “Next” button to continue.
  7. Choose the option from the list “Allow duplicates to be created” and then click on the “Finish” button.
  8. Once done, a new pop-up will come up asking you to provide an optional password. You can move ahead without providing it and click on the “OK” button and your OST file will be automatically saved in PST format at the selected location.

Use “Archive” for the conversion

Note: In this method, you need to enable the Archive Settings so that OST files get saved as a separate PST file in the system. It also keeps the mailbox size at an optimal level by saving the older emails in the archive folder.

Follow the below-mentioned steps to create an archive mailbox:

  1. First, you need to open Microsoft Outlook and click on “File Menu” present at the top left corner of Outlook.Click “Options” and then navigate to “Advanced”.
  2. Click “Auto Archive Settings” button present on the screen.
  3. Now provide the number of days for which to run the Auto Archive.
  4. Then provide the desired location by using the “Browse” button to save the archive file. Then click on the “OK” button to continue.
  5. The process will start and the mailbox items will be saved to the PST file automatically.

 Drag and drop to a new PST file 

drag and drop method to convert OST to PST Manually

    1. First, you need to open Microsoft Outlook and create a new PST file for your Outlook profile.
    2. To do so, click “New Items” from the Toolbar. Go to “More Items” -> “Outlook Data file”.
    3. Enter the file name and you can provide a password as well in the optional password box.
    4. Click on OK button and PST file is created.
  1. Now drag all the mailbox folders which you would like to export to the newly created PST file. Please note that you won’t be able to drag the Inbox and Contacts folder to the PST file. For that, you need to copy the folder from OST to PST.

OST To PST Converter Software [Recommended]

The different manual methods to convert OST to PST have a few drawbacks, as follows:

  • They are slow as compared to automated methods
  • They involve a risk of data loss
  • There are more chances of human error

In order to overcome these shortcomings, it is recommended to use an automated method for OST to PST conversion.

Stellar Converter for OST is an advanced OST to PST conversion software that makes this task quick and easy, without any risks or chances of human error.

This tool extracts all mailbox information from OST files and converts it into equivalent PST files. The mailbox hierarchy is preserved and none of your data is lost during the conversion process.

It also converts encrypted OSTs and IMAP OST files and has no file size limitations. It provides a free enhanced preview of emails, calendars and other mailbox items.

The best part is that it offers to do free OST to PST conversion for first 20 emails per folder. To know more, visit this link.

free download

To sum up

The OST to PST conversion is needed for avoiding hindrances to workplace tasks and productivity due to Exchange Server crash or unplanned downtime.

There are a few manual methods that can help achieve OST to PST conversion, which -though don’t cost – pose a few limitations. For instance, you can only convert OST to PST manually if you are using Microsoft Outlook with your original Exchange account. Also, these manual methods take longer to convert the OSTs and therefore wouldn’t suit a mass conversion need.

A software-based method is more effective for converting OSTs to PSTs, due to faster execution, comprehensive functionality (multi-format output, batch conversion, etc.), no chances of error, and a more seamless overall experience. The software is also available for free download and evaluation.


  1. Saul June 27, 2019
    • Shelly Bhardwaj August 14, 2019

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