Occasional Contributor



is it possible to convert OST to PST for all users at once using Powershell script?


and upload to o365?



Hi dear user,
You asked good question, if I give suggestion on my personal technical experience, PowerShell script is convenient only for technical user. It requires more technical expertise to convert and migrate OST to Office 365. But your question is for all user then you should probably use MailsDaddy OST to PST converter. This OST converter tool is specially designed to meet the OST to PST conversion requirement. Here you can export not only in PST but also in other file formats like HTML, MHTML, EML, RTF etc. Migrating OST file to Live Exchange Server can also be done using it. So use this application to instead using PowerShell script.

MailsDaddy OST to PST Converter tool is the most exclusive solution used to fix damaged & corrupted OST files and convert them into Outlook PST format. It enables users to migrate Outlook offline OSTdata into PST, EML, MSG, MBOX, MSG, RTF, HTML, Live Exchange Server, Office 365, and others. The utility exports OST to PST with maintaining original folder hierarchy text formatting, and email properties. The software also migrates contact and calendaring data. It has a free demo version that exports the first 20 data items of the OST file into Outlook PST format.

Yota OST to PST Converter is a user-friendly software that helps to migrate the entire data without any hassle. It is known as one of the best OST to PST conversion tool because it allows users to import OST to PST and other useful formats with complete accuracy. This utility doesn't require any technical knowledge for its use. The software has an interactive interface that guides the users through each and every step of migration process with detail description. Users can easily recover attachments, emails, tasks, contacts, calendar entries, notes etc. from the files using this tool.

OST is just a cache file that only helps you access your Outlook Profile Offline. Sometimes due to many reasons, if the OST file has corrupted, then you can delete the OST file from the local folder and can recreate the OST file from the network server. However, When the user profile has been deleted from the Network server and users don’t have the mailbox backup, they can use the local saved OST file to regain their mailbox data in the PST file format. That PST you can import to new Outlook profile without any hassle. Unfortunately, there are no free tools or PowerShell commands to convert the encrypted orphaned OST file. You have to go with 3rd party tools for this work. You can check the MVP discussion and take the idea about the some recommended OST converter tool available in the market,

You can convert offline IMAP, Outlook, or Exchange OST files to PST format using this utility without any additional work. The software offers a user-friendly interface that allows even non-technical users to convert OST files to PST files. You can convert 50 items from an OST file to PST format during the free trial time.
OST to PST Converter is a powerful OST to PST conversion tool that restores data from OST files. The software includes a slew of user-friendly features to enable a speedy and seamless conversion from OST to PST.

best response confirmed by Linkang (Occasional Contributor)
Hii, You can convert your OST files to PST by using these simple steps:-
1. Download Microsoft Outlook and go to the File menu.
2. Choose the Import/Export option.
3. Then, select the Export to a file option to export the desired file.
4. Select Outlook Data File (.pst)
5. Choose whether to export a specific folder or the whole account.
6. Check the Include subfolders box and add the subfolder if you want to add it.
7. Next, select a destination for the Export, and then click Finish

Hi @Linkang

As per my personal experience, you can use the Import/Export option provided by Microsoft in Outlook. 


Follow steps: 

If your Exchange profile is active and configured in Outlook. Also, it requires server connectivity. 


  1. Launch Outlook and click on the File tab and chose the Open & Export option 
  2. Now select the Import/Export option and select Export to a file, hit Next
  3. Select Outlook data file (.pst) and hit Next
  4. Select Profile which you want to export and then browse the location to save, at last, click Finish

This method is not applicable in the following situations:

  • Exchange profile deleted 
  • Server not connected 
  • Orphaned OST or another user's OST file 

In all these situations, you have to rely on third-party solutions. For the same, I recommend Windows OS users to use SysTools OST to PST Converter. 

Hi, @Linkang If the need to convert Outlook OST file to PST format arises, There are no PowerShell commands that can read OST files or convert OST to PST, the problem is that Microsoft never really exposed OST file format in .NET classes, which means PowerShell's got nothing to build on but there are some manual methods and third-party tools you could potentially use. One such trustworthy tool is Shoviv OST to PST file Converter.

So, as far as converting OST to PST using PowerShell is concerned, it isn’t feasible as of now.


Convert OST to PST file Manually:-


  • Open MS Outlook.
  • Click the File menu.
  • Select the “Import and Export” wizard or press ‘t’.
  • From the list, click the “Export to a file” option and then click Next button
  • Select Personal File Folder (.pst) and then click Next button.
  • Select the items to be exported or Click on parent root and check the Include sub-folders option.
  • Browse and select the target folder for saving the email items.
  • Click the Finish button.


In Outlook 2013, 2016, or 2019,

  • Navigate to File > Open & Export > Import/Export. This opens the Outlook Import Export Wizard.
  • Select Export to a file from the Import and Export Wizard window and click Next.
  • In Export to a file window, choose Outlook Data File (.pst) and click Next.
  • Choose the mail folders and items you want to convert to PST and check the 'Include subfolders' checkbox. Then click Next.
  • Click 'Browse' to select a save location to save the converted PST file and click 'Next.
  • Click 'Finish. Then enter a password or click 'OK' without entering the password.'



We'll need to use Outlook self to manually convert an OST file to a PST. Ensure that you can access the original Outlook profile.

  • Click File in Outlook.
  • Choose Import/Export from the list of options under Open & Export.
  • Choose Save as a file from the drop-down menu.
  • Choose a data file from Outlook (.pst)
  • Choose whether to export a specific folder or the entire account. Ascertain that Include subfolders is checked.
  • Click Next, then Finish after selecting an export destination. When the export is complete, you'll be given a PST file that you may use to import your emails into another account.




Stellar Converter for OST is extremely helpful tool.

@Linkang As a reminder to all respondents, we do not allow external third-party links in Tech Community. We'll be removing posts that include these links, or will remove links within posts, depending on the content. The question was about using a PowerShell script - if you must suggest a third-party tool, please do not link to it as self-promotion/advertising is against our code of conduct. Thanks for understanding and contributing to Tech Community.

Hi @Linkang


I am not sure that you are capable of converting OST files to PST format by using Powell script or not. As I belongs to a non-technical background, so I don't know much about this. I can only confirm you about these file format of OST and PST.


So, let me share you my thoughts. Once your Outlook gets disconnected than there is a OST file in background which contains all the data of your Outlook. When you are trying to connect back to Outlook, then you'll get an error. In that case, you can only import PST file to Outlook which is only a single option in Outlook. There is a need of converting your OST files into PST format.


Now, the question is can I convert those OST files into PST by using Powershell script or not. I don't confirm you about it. But I can share you some third-party tools which helps you! I usually preferred to ZOOK OST to PST Converter for my cases when I got these issues of ost and pst. This tool is so helpful in resolving these issues. You can also opt to use this and hopefully this will help you too!





Thanks and Regards

Steve Smith

Use Datavare OST to PST Converter and convert all OST data to PST file format. In a couple of clicks, complete OST file items into PST file format are exported by the software. With entire data integrity and ideal, OST mailboxes into PST file format are converted by the app. The best thing about this utility is it can work without installing MS Outlook. Any large, corrupt, and orphaned OST file into PST file format is exported by the software. To know the software working, download a free version that allows conversion of the first 10 items per folder.

@Linkang For a risk-free and efficient OST to PST Conversion process, users are suggested to use a modern OST to PST converter tool. It always gives accurate results without any data alteration. Softaken Offline OST to PST Converter easily converts OST to PST, PDF, EML, DOC, and 10+ file-formats including contacts, calendar, attachments, etc. Users can also remove encryption from OST files and preview its content before the conversion process. It also has a Date Range Feature that allows the users to convert only selected emails only.

The OST file format has one extraordinary capability that it lets users work offline. Other than that, it loses to its companion, PST. For backup, to merge data with a new Outlook profile, to access inaccessible OST, PST is the first choice. For converting OST to PST, there are two approaches available, one is manual, and the other are the professional tools. However, the manual method works only for the online OSTs; for orphan OSTs, users need to use professional tools.
The Weeom OST to PST Converter tool is a reliable, robust, and speedy solution to convert OST to PST files. It comes with an easy-to-communicate GUI along with numerous powerful features to get this task done.
Eminent Features of Weeom OST to PST Converter:
•It tackles the corrupt OSTs as well, recovers their data, and converts them to PST without
making any changes.
•This tool provides preview of both the corrupt & inaccessible OSTs on its interface before
conversion. Users can access them from the right pane of the tool’s interface.
•The PST split option is there to enable users to keep a limit on the PST file size as PST exceeds
over 50 GB corrupts.
•Using the filter feature of this tool, users can add or remove certain items from the conversion
as per the need.
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