Top 3 Methods to Convert OST to PST PowerShell for Outlook

Published By Jamie Kaler

Approved By Rollins Duke

Published On June 4th, 2025

Reading Time 10 Minutes Reading

Many users use to create an OST file to work in Offline mode to save data when they work offline. To open OST file’s data, users need connection with exchange server or convert OST to Outlook Data File. But what you are going to do if you do not have a server.

OST files and PST files are completely different from each other. Outlook does not offer any option to import OST files in Outlook directly. And you can’t open OST files with Outlook by using open with option. In such condition, the only option left is, convert OST File to Outlook PST file format and for this, we have two primary methods. So, if you are in need to convert OST files to PST format then please continue reading the blog.

Reasons to Convert OST to PST

• When Outlook profile or Exchange profile is deleted, then OST becomes orphaned. Export Outlook OST files to PST allows access to it again.
• It’s a reliable way to create backup of your mailbox data for future use or migration.
• PST files are portable and can be easily imported into Outlook on a different computer or user profile.
• If your OST file is corrupted and inaccessible, exporting to a PST file helps to recover and restore your data.
• OST files used by Exchange/IMAP. If you are switching to a POP account, it enables you to retain access to your old emails.
• OST file to PST Conversion helps to reduce mailbox size on the server, improving performance and avoiding quota issues.
• With PST files, you can access your emails offline when OST sync is not functioning or the server is down.
• Organizations may be required to convert OST files to PST for email archiving, auditing or legal purposes.

Free ways to Convert OST to PST format – Check out the options

When converting OST files to PST format, there are various free and reliable options such as Convert OST files to PST PowerShell, Outlook Import/Export feature and more available. We’ll go through them step by step in the next sections. So, have a look at this.

How to Convert OST to PST Using PowerShell?

Converting OST files to PST using PowerShell directly is not supported. As you need first need to convert OST to CSV then you can use Outlook import/export feature to import Comma Separated Value file then you can export PST file. Perform PowerShell Command to convert OST to PST:

1. PS C:\Users\Admin> $outlook = New-Object -ComObject Outlook.Application
   >>
2. PS C:\Users\Admin> $namespace = $outlook.GetNamespace (“MAPI”)
3. PS C:\Users\Admin> $inbox – $namespace.GetDefaultFolder(6) $namespace.GetDefaultFolder (6) # 6 = olFolder Inbox PS C:\Users\Admin> $messages =
4. PS C:\Users\Admin> $outputPath PS C:\Users\Admin> $outputPath PS C:\Users\Admin> $data @()
   $inbox. Items
   “C:\Users\YourUsername\Documents\OST_Emails.csv” “C:\Users\Admin\Documents\OST_Emails.csv”
   PS C:\Users\Admin> foreach ($mail in $messages) {
   >>
   >>
   if ($mail is [____ComObject] -and Smail.Subject) {
   $data += [PSCustomObject]@{
   Subject
   Sender To
   Received
   Smail.Subject
   $mail.SenderName $mail.To
   $mail. ReceivedTime
   BodyPreview = $mail.Body.Substring(0, [Math]::Min($mail.Body.Length, 100)) # Limit to first 100 chars
   }
   }
   }
5. PS C:\Users\Admin> $data | Export-Csv -Path $outputPath -NoType Information -Encoding UTF8
6. PS C:\Users\Admin> Export completed to $outputPath
7. PS C:\Users\Admin> $inbox – $namespace.GetDefaultFolder(6) # Inbox PS C:\Users\Admin> $contacts – $namespace.GetDefaultFolder(10)

Import Comma Separated Value to Outlook

1. Open Outlook and navigate to file.
2. Click on open and export and press on Import/Export.
3. Choose Import from another program or file and click on Next button.
4. Browse Comma Separated Value and press Next option.
5. Select mailbox data as you want to import.
6. Press Next to start import Comma Separated Value to Outlook.

Export PST from Outlook

1. First, open Outlook and navigate to the file.
2. Click on open and export and next click on Import/Export.
3. Choose Export to a file and press Next.
4. Select PST(Outlook data file) and hit on Next.
5. Choose the Outlook mailbox folder as you want to export.
6. Browse the destination path and press the finish to convert OST files to PST.

Method 2: Exporting your mailbox as a PST file

As Convert OST to PST via PowerShell is not reliable for all types of users. So, here we are going to explain Outlook Import/export feature to successfully export OST files to PST:

1. Log into Outlook using the Exchange account associated with the OST files. Additionally, to convert OST mails to PST, use this straightforward procedure:
2. Choose Files >Open & Export >Import & Export from the menu bar.
3. After selecting Export to a file, proceed to the next step.
4. Choose the second choice, Outlook Data File (.pst), and then click the Next button to proceed.
5. Select the folder from which you wish to export files and then click the Next button.
6. Select the location where you want to store the new PST file and the choices for dealing with duplicate items from the drop-down menu.

Note: Providing a password for the PST file is an optional step, and you can proceed without completing it.

Method 3: ‘Archiving’ can be used to Save OST emails to a PST file

The Auto Archive technique in Outlook will allow you to store the items from an OST file in a separate PST file by activating it. It is possible to keep the size of your mailbox moderate by using this strategy. Whenever the size of the mailbox increases, and there are several messages that are older than the mailbox and you do not require them to remain in the mailbox, you can quickly move them to the archive folder by selecting them from the message list. To activate automatic archiving in Outlook, just follow the instructions outlined below.

1. Open the Outlook app and select File > Options from the File menu.
2. Select Auto Archive Settings from the Advanced drop-down menu.
3. Choose the number of days you wish to perform auto archiving for and click “Save Changes.”
4. Choose the location where you want to save the archived file, as well as the archiving parameters, and then click Finish.
5. As a result, mailbox objects from your OST file will be saved to your PST file in accordance with your archiving preferences.

Method 4: Most Recommend Solution to Convert OST to PST without Outlook and Exchange

MailsWare OST Converter is the professional utility in order to convert multiple OST files to PST at once. The tool has the ability to import emails from Outlook OST to PST along with attachments. The application allows users to maintain all the properties while exporting OST files to PST format. There are only a few steps to import OST files to Outlook PST format. The steps are as follows:

Steps to Use OST to PST Converter

• Download the app by clicking on the download button.
• Open the software and select either the Select Files or the Select Folder options.
• Once the files are loaded, you may press the “next” button.
• Select PST from the list of available file types when prompted for a save location. Begin the procedure by selecting the target path and pressing the next button.

Benefits of OST to PST Converter Software

It is a safe and reliable application to convert Exchange OST to PST format. The tool allows you convert multiple OST files to PST format at once. With this tool, one can easily import OST emails to PST along with attachments. During OST to Outlook PST Conversion, the tool maintains all the properties. OST to Outlook PST Converter comes up with the very simple user interface. There are so many facilities provided by the tool which make it unique.

• It is a safe, secure, and reliable application to export OST to PST format.
• While converting OST to PST, the tool maintains all the properties.
• Exchange OST to Outlook PST Converter is completely Windows based application.
• The tool supports all the edition of Microsoft Outlook like 2019, 2016, 2013, 2010 & older editions.
• There is no file size limitation imposed on the tool to convert Outlook OST to PST format.
• With this tool, one can easily convert OST to PDF without Outlook installation.
• The tool allows you to convert selective Outlook OST files to PST without losing a bit of information.
• It also has the ability to split PST file by 2 GB, 5GB or 10 G as per the requirements.
• During Exchange OST to PST Conversion, one can also hit on the stop button to end the process.

Let’s Wrap Up

In todays guide, we have provided the free ways to convert OST to PST format. The methods that have been offered are entirely safe and secure. If you have Outlook and Exchange connectivity, the first and second methods described above are appropriate. However, if you need to convert OST files to PST without use of a third-party tool, you may simply download the MailsWare OST to PST Converter that has been recommended.

Helpful Questions

How to Convert OST to PST Using PowerShell?

To convert OST file to PST using PowerShell, you must have installed Outlook and configured the OST file. Start by enabling script execution with Set-ExecutionPolicy Unrestricted -Scope CurrentUser. Now, create an Outlook COM object using $outlook = New-Object -ComObject Outlook.Application and access the MAPI namespace with $namespace = $outlook.GetNamespace(“MAPI”). Browse OST file by specifying its path (e.g., C:\Users\\AppData\Local\Microsoft\Outlook\yourfile.ost). Then, define the PST output path (e.g., C:\path\to\output.pst) and add a new PST store.

How to Export OST to PST Without Outlook?

To convert OST files to PST without Outlook, use millions of trusted MailsWare OST to PST Converter as these tools extract data from orphaned, corrupted, or inaccessible OST files and convert them into PST format without requiring Outlook installation or original profile data.

How to Convert OST to PST Using Outlook?

To convert OST files to PST using Outlook you need to follow the process first you need to Open Outlook with the configured OST file. Go to File > Open & Export > Import/Export > Export to a file > Outlook Data File (.pst). Select folders, choose a destination, and complete the export. This creates a PST file from your OST data using Outlook.