Stellar Converter for OST

Top Use Cases

When to Use OST to PST converter tool?

Export OST to PST

Extract Mailbox Data

If you delete a user mailbox from Exchange without a backup, you can only access the mailbox data via the OST file. However, you cannot recreate or restore the OST file if the Exchange user account has been deleted from the Active Directory. The Stellar OST Converter tool converts the inaccessible OST file into a PST file, which can imported into Exchange Server.

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Offline Outlook Data File (.ost) Synchronization Fails

Offline Outlook Data File (.ost) Synchronization Fails

If the OST file fails to synchronize, it means the file is inaccessible or the mailbox is disabled/deleted from the server. If the OST is inaccessible, you can rebuild the file and download the mailbox data from the server. However, in case the mailbox is deleted from the server, then it is not possible to rebuild the OST file. In such a case, you can use Stellar Converter for OST to extract the mail items from OST file and export them to PST file, existing Outlook profile, live Exchange Server, or Office 365.

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Migrate from Hosted Exchange to Microsoft 365

Need to Consolidate

Are you using Hosted Microsoft Exchange service? You don't have access to your email services, not having archive services available, and are not able to restore email services due to a compromised server. With an Outlook data file (.ost) available, you can restore and move all mailbox data to Office 365/M365. Stellar Converter for OST Technician converts OST files to Microsoft 365 while retaining the original folder hierarchy, ensuring a quick migration without any risk of data loss.

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Key Features of Stellar OST to PST Converter

Software Important Capabilities

Converts Large-Sized OST File

Converts Large-Sized OST File

Stellar has rigorously tested its OST to PST converter tool for handling large OST files efficiently. The software performs the fastest conversion of large OST to PST, aiding in scenarios where Exchange Server has crashed, inaccessible, or is experiencing synchronization issues. It seamlessly converts OST files to PST and extracts the data with 100% precision.

Conversion of Encrypted OST File

Conversion of Encrypted OST File New

When attempting to open an encrypted OST file, an error may occur, resulting in loss of access to the mailbox data. Converting the encrypted OST file to a PST (Personal Storage Table) file can solve this problem. Stellar's OST to PST converter converts the encrypted OST to PST, thereby enabling access to the mailbox data.
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Auto-Locates and Lists Outlook Data File

Auto-Locates and Lists Outlook Data File

Stellar OST to PST conversion tool auto-locates and lists the OST files of IMAP, Exchange or Microsoft 365 email profiles configured in Outlook. This allows you to quickly select the OST file, scan it, extract mail items, and save the extracted mail items them in PST or other supported format. You can also browse and select the OST file manually or use the ‘Find’ option to search and select the OST file for conversion when the location is not known.

Extracts All Offline Outlook Data File (.ost) Items

Extracts All Offline Outlook Data File (.ost) Items

OST to PST converter Tool extracts all items from OST files, including emails, attachments, contacts, calendars, tasks, notes, and journals. The tool performs accurate OST to PST conversion, preserving the original integrity of mailbox items. It is the ideal solution for all situations where users need to move OST files to PST and convert OST to PST without an Exchange profile. 
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Reviews & Feedback

Recommendation by Microsoft MVPs

Edward van Biljon(MVP, Microsoft Community Contributor)
Nuno MotaSenior Exchange and Office 365 Consultant
Daniel BeatoSystem Administrator

Other Important Features

Know your Product Better

Free Preview of Offline Outlook Data file

Free Preview of Offline Outlook Data file

The software displays a detailed preview of the mailboxes items stored in the converted OST file. Users can click on a folder, email, calendar, or other mailbox items listed in the preview pane to view their contents. This preview function aids in identifying and extracting specific items from the offline Outlook data file (OST).

Sorts and Organizes the Messages

Sorts and Organizes the Messages

The OST PST converter software extracts OST file data in an organized manner, maintaining the original arrangement of email items. Once the OST scanning is complete, the software allows you to sort and organize emails by Date, From, To, Subject, Type, Attachment, Importance, and more.
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Find and Save Individual Mail Items

Find and Save Individual Mail Items

With the “Find Message” button, you can open the “Find Message” window and search for specific emails or mail items using various parameters such as “To”, “From”, “Subject”, “Message text”, etc. Once you find the desired email, you can then right-click on it to save it to your preferred location in PST, MSG, EML, RTF, HTML, or PDF file format.

Allows to Save and Load the Scanned File

Allows to Save and Load the Scanned File

The OST to PST converter tool allows the user to save the "scan" information of the OST file as a DAT file, which can be loaded later for conversion. This feature helps split the OST to PST conversion process into two stages, doable at different times or on different systems.
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Auto-Split Large PST Files

Auto-Split Large PST Files

The OST to PST conversion software includes an Auto-Split option that automatically splits an oversized or large PST file at around 45 GB while saving the converted email items from OST files. This feature helps prevent corruption of the PST file due to its size.

Exports the OST Data to Office 365

Exports the OST Data to Office 365

The software can export the converted mailbox directly to Office 365. It allows users to log in to an Office 365 account and export the mailboxes directly from the user interface. The OST to Office 365 Export feature is available in the Technician Edition of the software.

Converts OST into Multiple File Formats

Converts OST into Multiple File Formats

The OST to PST conversion tool allows users to extract mailbox data in various file formats, including PST, MSG, EML, RTF, HTML, and PDF. Additionally, users can view the content of the OST file in applications such as Outlook, web browsers, PDF readers, text readers, etc.
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Converts Multiple OST Files in a Batch

Converts Multiple OST Files in a Batch

The tool can convert multiple OST files to PST files in a single batch process. This batch conversion feature is particularly helpful when an organization switches to a new email service and needs to extract mailbox data from multiple OST files. This feature is available in the Technician Edition.

Preserves Original Folder Hierarchy

Preserves Original Folder Hierarchy

This OST to PST conversion software converts the OST file while preserving the folder hierarchy and structure. It ensures the integrity of emails and other mailbox items during the conversion process. After conversion, you can preview the converted OST items before saving them to PST or any other format.

Compacts PST File

Compacts PST File

The Technician edition of the software provides an option to compress PST files, allowing you to reduce the size of large PST files. This option also enables you to extract attachments from the PST file and save them in a separate folder, while preserving the links in the PST file. Additionally, you can use this option to save all attachments in a new PST file.
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How to Use Stellar Converter for OST

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Choose as per your need


Convert OST to PST and extract all mailbox items



SAVE $20
  • Converts OST into PST format
  • Lists all OST files from the default location
  • Converts All Offline Mailbox items with Free Preview
  • Saves & loads scan data
  • Auto-splits large PST files while saving the mail items
  • Advanced filter options for precise conversion
  • Saves the mailbox data in PST, EML, MSG, RTF, HTML, and PDF file formats

Convert multiple OST files and export to Exchange or Microsoft 365



SAVE $50
  • Includes all features of Corporate
  • Converts multiple OST files in batch
  • Compacts & Splits PST file
  • Exports to live Exchange
  • Migrate to Microsoft 365
  • Exports to MS Outlook
  • Exports contacts in CSV file

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Best Seller

All features of Technician + 7 more tools



SAVE $300
  • Includes all features of Technician
  • Repairs corrupted PST file
  • Recovers the mailbox items
  • Merges multiple PST files
  • Removes duplicate emails
  • Recovers lost password of PST
  • Restores the deleted emails

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How Stellar Converter for OST Software Helped Southend-on-Sea Borough Council

The client organization retrieved vital business mailbox data that would have otherwise been lost, ensuring the integrity of emails, attachments, and components for archival purposes. Stellar Converter for OST facilitated rapid extraction with minimal administrative effort, delivering high-precision, efficient, and reliable results to meet the client's needs effectively.

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Customer Verdict

This is a very handy and easy to use software that I would recommend to anyone.

Southend-on-Sea Borough Council, Essex, England

USC Inc. Successfully Migrates Mailbox Data From OSTs To Office 365

USC achieved seamless 100% mailbox migration to Office 365, including data from OST files, meeting deadlines with minimal manual involvement. The OST to PST converter also recovered deleted mailbox data without risking file corruption.

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Customer Verdict

This is a very handy and easy to use software that I would recommend to anyone.

United Software Consultants, Inc.

Marcrom restores its new server with stellar's ost to pst converter

Ivan found it challenging to select effective software but was highly satisfied with Stellar Converter for OST on his third attempt. It fulfilled all his business needs and outperformed other options, prompting him to endorse Stellar Data Recovery's superior products.

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Customer Verdict

This is a very handy and easy to use software that I would recommend to anyone.



You're in Good Hands


Most tested. Most awarded. For over 30 years, we’ve been recognized as experts

q1 q1
ExpertExchange star

Stellar Converter for OST saves your business & time

With its great features, Good Interface, and ease of using Stellar OST to PST deserves 10 out of 10.

MakeUseOf star

Convert OST files to PST easily

Stellar Converter for OST makes OST to PST conversion process hassle-free

SpiceWorks star

Awesome OST TO PST Software

Stellar OST to PST converter has worked wonders for Outlook 2003 to 2016 conversions of OST Files. This application I use and resort to. star

Helps admin to easily convert any OST file to PST

It converts an entire OST file, or items within an OST file, into a PST without changing the original content format or structuring.

TweakTown star

Powerful OST to PST Converter Tool

Stellar Converter for OST converted all items from OST file to PST with complete integrity & precision.


Technical Specifications

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About Product
Stellar Converter for OST
License: Single System
Edition: Corporate, Technician, & Toolkit
Language Supported: English, Deutsch, Français, Italiano, Español, 日本語
Release Date: November, 2023
System Requirement
Processor: Intel compatible (x64-based processor)
Memory: 4 GB minimum (8 GB recommended)
Hard Disk: 250 MB for installation files
Operating System:
(64 Bit only)
Windows 11, 10, 8.1, 8, 7


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*Free Demo Version allows you to preview all the converted file data.



Follow these steps to convert an OST file into PST file by using the software:

  1. Run Stellar Converter for OST
  2. Browse and select the Offline Outlook Data File (.ost)
  3. Click 'Convert' button to start the conversion process
  4. Click 'Save Converted File' button to save the mailbox data
  5. Select Outlook Data File (.pst) as the file format to save the converted data in PST file
  6. Click ‘Browse’ to specify the location and click ‘OK’ to save the data

The software will scan the OST file & list all the items preview in a tree-structure view. Verify the data and save them at your destination location.

The OST to PST Conversion Software is best option to migrate Hosted Exchange mailboxes to Microsoft 365.

  1. Run Stellar Converter for OST Technician Edition
  2. Select the Offline Outlook Data File (.ost)
  3. Click 'Convert' to start conversion process
  4. Click on 'Save Converted File' button to save OST file
  5. Select 'Export to Microsoft 365' and click on 'Next' button
  6. Enter Office 365 or Microsoft 365 credentials and click OK.
  7. This will export the OST file to Microsoft 365 mailbox directly

Stellar Converter for OST Technician Edition will scan the OST file and list all the mailbox folders in the left pane. Click on a folder to preview its items and migrate them directly to Microsoft 365. Download Now

  1. Launch Microsoft Outlook.
  2. Open File tab.
  3. Click on ‘Open & Export’
  4. Now Select Import/Export option.
  5. Click on ‘Import from another file or file’.
  6. Click on ‘Next’ button.
  7. Select Outlook Data File (.pst)
  8. Click on the Next button.
  9. Browse the file to import & Click on the ‘Next’
  10. Choose Finish.

Now Microsoft Outlook will start importing the items of your Outlook Data File (.pst) immediately.

The Demo version of the software converts the Outlook OST file and allows to preview all the mailbox data.

Yes, Stellar Converter for OST allows you to search for the OST files (Offline Storage Table) stored in any folder, sub-folder, or drive in your system. Use 'Find Outlook File' feature of the software to locate the OST files.

You would need to convert an OST file into PST file in any of the following cases:

  • You need to access the emails from a mailbox that is deleted from Exchange
  • You are facing issues while synchronizing Outlook with Exchange Server
  • You need to migrate the email organization to a different platform
  • You need to recreate or rebuild the OST file in case of an Exchange Server crash/disaster
  • You are facing difficulty with Outlook Import/Export Wizard
  • You need to change the location of the offline Outlook Data File (.ost) in Microsoft Outlook
  • You need to move Outlook OST file to another disk

Or facing an error while accessing OST file –

  • Outlook is using an old copy of your Offline Folder File (.ost). Exit Outlook and delete the .ost file, and restart Outlook.
  • errors have been detected in the file outlook ost
  • outlook cannot configure OST file

The total time for converting an OST file into a PST file depends upon the OST file size. Stellar Converter for OST takes approx. Seven minutes to convert per GB of OST file into PST.

The software can save the converted OST file into MSG, EML, PDF, RTF, or HTML file formats.

If you face any problem during or after an OST file conversion, you can contact the Stellar support team:

The software is available in two variants – Corporate & Technician. If you only need to convert an OST file into PST file, then you should go for Corporate. If you want to convert and also compact or split a PST file, then you should use the Technician edition. The Technician edition can also export the OST file data to Office 365.

Stellar Converter for OST is available in three different editions: Corporate, Technician, and Toolkit. The Corporate edition is available with a single-device license and can be installed only on a single device or system. The Stellar Converter for OST - Technician and Toolkit editions are available with a Bulk Licensing option. If you choose Technician or Toolkit edition, you can purchase licenses based on the number of devices or systems you have. At a time, you can purchase bulk licenses for Technician and Toolkit editions for 1, 5, 10, 25, 50, 100, 200, or 500 devices or systems. Read More

Yes, the software converts OST file that is not connected to Exchange Server.

Yes, the software guarantees OST to PST file conversion; however, we strongly recommend trying the free Demo version of the software which previews the mailbox data stored in OST and also converts up to 20 mailbox items per folder. After ascertaining the software effectiveness, you can activate it with a license key and then convert & save all mailbox items in PST or other file formats.

Yes, you can open the converted OST on another system after saving the OST file in a format such as PST, EML, RTF, or other supported file formats.

The software does not perform any action on the corrupted OST file. It converts the corrupt OST file in PST file, thus enabling access to the OST file data.


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