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OST to PST file converters are a boon when you need to store Outlook data comprising emails, contacts, calendars, tasks, notes, and attachments.

OST (Offline Outlook Data File) and PST (Personal Storage Table) are crucial for users of Microsoft 365, MS Exchange, IMAP, or POP3 accounts.

While we’ve gone into the detail with the best features of each so that you have all the information about the best OST to PST file converters at your fingertips; we’ve also created the below table; to give you a glimpse of what is to come:

Product Name Description
Stellar Award-winning, secure OST to PST conversion with advanced filter options. Explore
SysTools Premier choice, converts inaccessible OST to PST with selective item export. Explore
Recovery Toolbox Converts, repairs password-protected OST files, handles damaged files, no domain connection. Explore
OST to PST Converter Advanced tool, secure conversion of OST files to PST format. Explore
Aryson Reliable tool for converting OST to PST, MBOX, MSG, EMLX, etc. Explore
MailsDaddy Efficient bulk conversion, recovers data from corrupt OST files securely. Explore
Shoviv Automated, fast conversion with options to save in various formats. Explore
Kernel Trusted by MVPs, converts OST to PST, PDF, MSG, EML, etc. Explore
BitRecover Certified by MVPs, converts inaccessible OST to PST, supports multiple languages. Explore
eSoftTools Award-winning tool, recovers, and converts OST to PST with advanced features. Explore
KDETools Secure migration, converts OST to PST, MBOX, MSG, EMLX, etc. Explore

What is an OST and a PST file?

Office Outlook Data File (OST) and Personal Storage Table (PST) are the two file formats used by Microsoft Outlook, where all email application data is stored.

OST files enable offline access and synchronization with an Exchange Server, serving as local caches for mailbox data. PST files, in contrast, act as standalone storage files, allowing users to archive, backup, or migrate mailbox data independently of server connections.

While OST files sync changes with the server, PST files offer users manual control over their data without requiring constant server connectivity. However, to open an OST file in Outlook it necessitates conversion into a PST file.

Why convert an OST file to a PST file?

The conversion of the OST to PST file provides the users with greater flexibility and control of data because it allows the users to manage Outlook mailbox information with assurance of its intactness in all eventualities.

  • By converting the OST files to PST format, one is able to easily migrate the emails, contacts, and calendar items from one email account or server to another.
  • Users can safeguard and back up their Outlook data. Standalone PSTs provide users with an easy way to save important emails and items.
  • To recover crucial data from corrupt or damaged Outlook OST files and save them in a PST format.
  • Updating the Outlook configuration can be done seamlessly, along with converting OST data to PST format for smooth transfer. Make use of this simple process and update configurations effortlessly.
  • If you want an OST file accessed or opened on another computer that does not even have the same Exchange connection, then you may be required to convert it into a PST file.
  • The OST to PST conversion feature can help in meeting business as well as legal standards by providing older email data within a properly organized format for access.

In the following subsections, let’s see some of the best OST to PST file Converters.


Stellar is one of the oldest companies in the data recovery sector for the last 30 years. During this tenure, the company received over 120 awards, trusted by Fortune 500 companies, and served over 3 million customers across 190 plus countries.

Stellar is a worldwide leader in Data recovery software & services with more than 80+ DIY software tools and Physical Lab services with Class 100 clean rooms in India & Netherlands catering to worldwide customers who require physical data recovery & file repair services.

Stellar’s OST to PST converter is a trusted software for Microsoft MVPs and IT admins that accurately converts all emails, attachments, contacts, calendars, and notes from inaccessible or orphaned Outlook Offline Storage Tables (OST) files with no file size limitation into PST format.

Additionally, it safeguards the original integrity of mailboxes even when moving between two different formats without requiring access to the Exchange profile.

Stellar OST to PST converter is award-winning and trusted by millions of users, which is 100% safe and secure to use. The software has two editions – Corporate and Technician.

Stellar Corporate Edition is a comprehensive tool offering an easy and efficient way to convert OST files into PST format. It lists all the offline mailbox items with a free preview, has auto-splitting capabilities for large PSTs while saving all mail items, provides advanced filter options for precise results, and offers multiple file formats like EML, MSG, RTF, HTML, and PDF after conversion.

Stellar’s Technician Edition comes with more advanced features, and it is a must-have tool for professionals who need a wide range of features. It comprises all corporate features in addition to converting multiple OST files into Exchange or Microsoft 365, exporting the data to Office 365, directly Import the OST file data in Outlook, Microsoft 365, and Live Exchange, batch process several OSTs for conversion, and split large PST file in sizes up to 50 GB.

Stellar’s Toolkit Edition for Outlook provides an advanced 8-in-1 software package that supports all versions of Microsoft Outlook. This versatile tool facilitates the users and the administrators to carry out activities such as repairing corrupt PST files, transforming inaccessible OST files into PST, splitting and compacting PST files, optimizing the PST size, merging multiple PST files, eliminating duplicate items, recovering deleted emails and passwords to ensure smooth operation and optimum performance of Outlook.

Furthermore, it provides a Compact PST File Option that helps compress large stored data by compressing their size – making Stellar Technician ideal for enterprise-level businesses.

Top Features

  • Allows the user to extract the mailbox data in different file formats, such as PST, MSG, EML, RTF, HTML, and PDF.
  • It supports Outlook 2021 and earlier versions such as 2016 and 2019.
  • The tool also enables users to export their data directly from the hosted Exchange server into MS 365 or repair/compact the existing OST file(s).
  • Quickly and accurately converts large-sized OST files with 100% precision
  • Recover inaccessible emails from the Exchange Server, migrate them securely to Office 365/M365, or save them as PST.
  • Easily converts encrypted OST files into PST files for easy access and retrieval of mailbox data without data loss.
  • Its technician edition can directly export the OST to PST-converted files to Office 365.
  • Extracts OST file data in an organized manner while maintaining the original arrangement of mail items.
  • Its preview feature helps users to easily and quickly examine their mailboxes and select specific items for conversion from within the converted OST file without any hassle.
  • Auto-locates OST files and provides a list for quick selection, allowing users to scan, extract mail items, and then save in the desired format.

Users can try the Steller free edition before buying the software, which allows free OST file to PST file conversion, preview in detail, and extracts 20 emails per folder. Whew! That’s a lot!


SysTools OST to PST Converter is the premier choice of Microsoft MVPs for converting inaccessible, orphaned, offline, and corrupted OST files into Outlook-supported PST format. It can easily convert emails, calendars, contacts, and tasks in MS Outlook even when the Exchange Server has crashed or the mailbox dismounted.

SysTools OST to PST Converter enables users to effortlessly convert multiple offline storage table (OST) files into portable personal storage box (PST) format at once. It supports the migration of emails, contacts, journals, and other mailbox items along with multiple document formats like PDF, TXT, HTML, CSV, MHT, DOCX, RTF, etc., for successful conversion in the form you desire.

It includes features such as selective item export from any folder/category and loading and saving scan progress, allowing faster rescanning capability on large-sized files, offering ease-of-use during the conversion process even when complex Exchange Server crashes occur, leading users, both individuals and organizations easy access their mailbox data without much effort through MS outlook platform.

It also includes features such as scan and load the saved option for faster rescanning of large OST files without compromising data integrity. The converter supports a range of MS Outlook-compatible email services like IMAP, Office 365/Exchange, Hotmail,, etc., allowing you to transfer hosted Exchange or online Exchange-based OST files in one go.

It is available for all versions of Windows OS as well as Mac operating System downloads.

Recovery Toolbox

Recovery Toolbox is a comprehensive software that excels in the conversion of Microsoft Outlook files, catering to a wide range of versions and scenarios. It flawlessly converts *.ost files from Outlook 97/98/2000/XP/2003 in the ANSI format, as well as .ost files from MS Outlook 2007/2010/2013/2016/2019/2021 in UNICODE format.

The tool demonstrates its versatility by converting password-protected and encrypted .ost files, even handling damaged ones with ease. Users have the flexibility to split the resulting PST file into volumes of a user-defined maximum size, providing efficient data management.

Furthermore, the software allows the convenient saving of items such as MSG, VCF, EML, or TXT files, offering diverse output options. It goes beyond conventional recovery methods by converting *.ost files even after a failed ScanOST recovery attempt, and doesn’t require a connection with a Windows Domain Controller for the conversion process.

Notably, the software empowers users to perform OST2PST conversion without the need for Microsoft Exchange Server, ensuring autonomy and ease of use.

The software doesn’t shy away from dealing with security measures, offering the ability to read and repair password-protected .ost/.pst files, as well as recover data from encrypted PST or OST files, providing a comprehensive solution for Outlook file recovery and repair.

OST to PST Converter

OST to PST Converter is an advanced tool designed for Windows users with Microsoft Outlook installed on their computer or server. It lets you quickly and securely convert Exchange Server/Outlook (*.ost) files into Personal Store Folders (.pst), which can be viewed in any compatible email client such as MS Outlook, Live Mail, Thunderbird, etc.

The program supports a wide range of file formats, including *.msg (Microsoft Office and Exchange), .eml ((Microsoft Outlook Express, Live Mail), .vcf (RFS822 contact storage format used by PIMs), and txt format.

With its easy installation and simple user interface – no internet connection required – OST to PST Conversion Tool is ideal for anyone looking to transfer data from one system or platform to another safely and efficiently.

Top Features

  • Convert OST files to UNICODE format (Outlook 2007 or higher) and ANSI format (Outlook 97…2003).
  • Reads password-protected and encrypted *.OST files without authentication from a Microsoft Exchange Server or Windows Domain Controller.
  • Convert OST files of any size and damaged OST files.
  • Preview the contents of an OST file before conversion.
  • Enable selective conversion, allowing users to choose specific data for conversion into an OST file.

The software can be downloaded in any of the three editions: Personal, Business, and Site. There is also the feasibility of using the software online to convert OST to PST files.


Aryson’s OST to PST Converter Software is an ideal solution for organizations and individuals who need a reliable tool that can convert MS Outlook OST files into popular file formats like PST, MBOX, MSG, EMLX, EML, or CSV.

Many Microsoft MVPs IT Administrators and other software companies prefer Aryson because of its safety and security features with 100% accuracy on all conversions.

The software also supports various web-based email clients like Office 365, Yahoo Mail, Gmail, Thunderbird, etc. The converter enables users to extract mailboxes, including emails, contacts, agendas, tasks, notes, and journals, from their inaccessible OST data in just a few clicks.

Users on Windows, Linux, and Mac platforms can use it, making it a very versatile and convenient choice.

Top Features

  • Export both individual and bulk Outlook OST data items, including emails, contacts, calendar entries, journals, and notes, to CSV files.
  • Safely extract OST mailbox items, ensuring the preservation of data integrity and the hierarchical structure of mailbox folders.
  • Save OST mailboxes in various non-email file formats such as PDF, HTML, MHTML, DOCX, TXT, DOC, DOCM, and JSON.
  • Options to save calendars from OST mailboxes in ICS file format.
  • Maintain the originality of data and the structured hierarchy of mailbox items during the OST to PST conversion process.
  • Assist in exporting or converting both individual and batch OST files, offering the flexibility to specify date ranges as needed.

This software offers a free evaluation through its demo version and enables users to convert up to 50 email items per folder from an OST file into PST or another file format/webmail client at no cost.


MailsDaddy Convert OST to PST tool provides an efficient solution for bulk conversion of inaccessible or corrupted Offline Outlook files into the desired output format. This reliable utility is easy to use and helps quickly recover data from corrupt, damaged, or inaccessible OST files without any alteration while preserving the original folder structure.

It enables users to convert unlimited Outlook data files with a fast processing speed in a quick time. It has powerful features that make it simple and effective in converting OST files into PST, Office 365, Live Exchange Server, MSG, EML, and MBOX with its Folder structure intact.

Moreover, users can choose single or multiple large offline/encrypted files at once backed up by the read/unread status of emails preserved along with other mail formatting flags like color coding, etc.

Top Features

  • Effortlessly transform all information from OST to PST format, encompassing emails, attachments, folders, contacts, and calendars.
  • Seamlessly imports the entirety of OST mailbox data into Office 365 and Live Exchange Server.
  • Rapidly recover deleted emails, calendars, contacts, tasks, notes, and journals from the OST file softly.
  • Utilize an advanced feature to search and identify all .ost file extensions within a chosen directory or drive.
  • Leverage the sophisticated algorithm of the OST to PST converter to repair highly corrupted, damaged, or orphaned OST files.
  • Exercise the option to split large OST data files during the OST to PST conversion process.

This OST to PST Converter supports Microsoft Outlook 365, 2019, 2016, 2013 & 2010 for the conversion of large data files. With this user-friendly tool, users can effortlessly achieve a seamless migration between Windows 11/10/8/7 and Win XP. In the demo edition, one can preview all information but is limited to exporting only 20 items per folder.


Shoviv OST to PST Converter Tool is the best-automated solution, which has been specifically designed for instantly converting Outlook Offline Storage Table (.ost) files into readable and accessible PST files.

It has a strong retrieval engine that assists it in easily bringing back lost emails, contacts, tasks, and journals from damaged or corrupted.OST file formats.

It uses modern algorithms that enable an unlimited size of OST data file conversion without limiting managing a lightning speed even when several other conversions are performed at the same time.

And that is not all, as this tool also provides the additional option to save exported Ost data in various other popular email formats such as MSG, EML, vCard, and HTML format files, which makes this complete conversion solution one of the most comprehensive available solutions for conversion today.

Top Features

  • Users have the flexibility to set the size for the resulting PST file for efficient splitting.
  • Incorporates an advanced incremental export feature.
  • Meticulously maintains folder hierarchy and preserves data authenticity.
  • You can save OST file items in various formats such as HTML, EML, vCal, vCard, MSG, and more.
  • Users can effortlessly add multiple OST files without encountering any size limitations.
  • Ensures the rapid and precise recovery of OST files that have been difficult to delete.
  • The application swiftly and flawlessly converts OST files to PST.
  • It is possible to export OST files to Office 365

This software works with all Microsoft Outlook and Windows versions and offers a free trial to convert the first 50 items/folders from OST to PST for users to try its features.

Kernel Data Recovery

Kernel Data Recovery tool for OST to PST Converter is a trustworthy tool favored by Microsoft MVPs and IT administrators, enabling users to efficiently convert inaccessible Outlook data files (OST) into various output formats such as PST, PDF, MSG, EML, etc.

This software facilitates the accurate conversion of emails, attachments, contacts, distribution lists, calendars, and tasks from OST format before saving them in Exchange Server/Office 365 accounts or in personal profile stores like Google Gmail,, or other IMAP servers.

Kernel Data Recovery is a comprehensive tool designed to provide better support for bulk and large-sized OST files, with an enhanced preview mode that displays calendar entries along with their color codes. It also enables complete recovery of all kinds of attachments in emails as well as faster saving of the recovered items at your desired location.

Top Features

  • Maintains folder hierarchy and data authenticity flawlessly
  • Recovers and exports NST files to PST, live Exchange, and Office 365
  • Utilizes advanced filters for converting specific emails and other elements
  • Compatible with the conversion of IMAP OST files
  • Transforms all components of the mailbox, including emails, attachments, contacts, calendars, and more
  • Restores permanently deleted items from the Outlook mailbox with full integrity
  • Facilitates the addition of multiple OST files without any size constraints
  • Stores OST file items in formats such as PDF, MSG, EML, MBOX, HTML, and Office Document files
  • Supports multiple file conversions at once with its powerful batch feature

The free trial version offers users a chance to test the functionalities before purchase, saving up to 25 items per folder in PST, MSG, or EML file formats. With its integrated search feature, you can quickly locate all OST files on whatever system drive or folder specified without needing manual searches.


For reliably converting inaccessible, corrupted, and orphaned OST to PST file format quickly and easily, BitRecover’s Outlook OST Converter tool provides the best solution. The software is certified by Microsoft MVPs. 

It converts emails, contacts, calendars, journals, etc, along with their attachment in original formats such as PDF, PPTX DOC & XLS without any size limitation from offline and hosted exchange server files into PST format even if they are a password protected or encrypted. 

Users can create the required size of split PST files while folder mapping options are also provided in 5 different languages, including Dutch, French, German, Spanish, and Swedish. All this is done without requiring the installation of an Exchange profile or Outlook on the user system, making it a perfect off-site conversion solution. 

Top Features

  • Automatically load and showcase a preview of the configured profile’s OST file.
  • Offer multiple advanced filters for exporting specifically required data.
  • Convert orphaned OST to PST without any compromise on data integrity, content modification, or encountering errors.
  • Adjust the output file size as per your needs to prevent PST file corruption and potential data loss.
  • The tool enables the export of encrypted OST files to the PST format.
  • Choose to convert only selected folders from OST to PST for a more tailored migration.
  • Assist in converting orphaned OST to PST without requiring an Exchange profile or server connectivity.
  • Ensures data integrity is maintained while converting data from an OST file to a PST file.

This multiple award-winning software offers a free demo version for evaluation but with certain restrictions. 


eSoftTools is an award-winning and robust tool for recovering offline Outlook (.ost) files and converting them into a personal storage table (.pst). Bulk conversions are facilitated with the best available quality. Its advanced features make the recovery process even more reliable. 

It enables easy extraction of mailbox emails along with attachments, calendar items, contacts, etc., in user-friendly new PST formats and EML/MSG/EMLXs HTML documents or vCard format. 

Users have access to additional functions such as being able to convert Password-protected and encrypted.OST files into other mentioned document forms at their own discretion without loss of any important information present in these sensitive databases.

Top Features

  • Import OST directly to your Office 365 account seamlessly, ensuring no loss of crucial data.
  • Utilize the PST Split feature to divide the resulting Outlook PST file into smaller, more manageable parts.
  • Effortlessly recover various types of data from a corrupted OST file in just a matter of minutes.
  • A built-in feature allows the selection of specific mailbox folders for conversion.
  • The tool is crafted with a focus on maintaining the hierarchy of folders in the resulting PST output files.
  • Explore the capability to migrate to MBOX from OST when Outlook access is unavailable, making it compatible with over 25 email clients.
  • A powerful feature that reads and analyzes both OST and PST files, facilitating their import into any IMAP server account.

All versions of both Outlook and Exchange software can be applied while using this powerful solution. It also supports IMAP account recoveries and conversion processes simultaneously. Its trail edition saves 25 items per folder from OST Mailbox to any format on your desired location.


KDETools OST to PST Converter is a reliable and advanced software that facilitates the smooth migration of large-sized data from the Outlook Data File (OST) format into several industry standard file formats like Outlook PST, MBOX, MSG EMLX CSV, etc.

It also allows its users to migrate their emails directly into cloud-based email services such as Office 365, Yahoo, Gmail, iCloud, GoDaddy email, Amazon WorkMail, Thunderbird, etc.

KDETools has been trusted by millions of customers for its secure transaction, 30-day money-back guarantee, 24/7 free technical support, and lifetime free upgrade facility. It also offers no file size limitation and 100% conversion with zero data loss and a top-notch Comodo security protocol SSL connection.

Top Features

  • Users can easily and swiftly convert their Outlook OST files into 15+ different file formats without any loss of data.
  • Its technician version has the capability of ‘Batch Conversion’, which allows users to quickly convert multiple OST files into PST format simultaneously.
  • Directly migrate OST to Office 365 Cloud.
  • Transfer OST data to Exchange Server Live without intermediary steps.
  • Convert OST calendars and contacts to vCal individually.
  • Recover and transform inaccessible OST files.
  • The technical version effortlessly changes PST, OST, and NST files into the preferred file format.
  • Preserve the original structure of metadata and folders during the conversion process.

KDETools offers full compatibility with all recent editions of Microsoft Outlook, Exchange Server, and Windows, including 2016/2013/2010 versions for each. Its free version can be used to preview the converted files.

What to keep in mind while choosing an OST to PST File converter?

Some of these are a few points to consider while shot listing an OST to PST File converter:

  • While selecting a converter, ensure that the tool is compatible with your Outlook and OST files — some only work for specific versions of both. Make the correct decision, taking into account careful considerations, so there isn’t any chance of problems popping up later.
  • Outline your requirements to define what exactly you need so that essential features can be identified and their capability assessed for each tool. It would help you get the best of the tool at the right price for your specific needs.
  • Ensure that it has facilities like batch conversion, selective item export, and decryption ability, among some of the important features, before finalizing the one.
  • Select one such OST to PST file converter from a trustworthy company that provides a fast and quick conversion of your files from the OST format into that of the PST.
  • Select a converter that converts the files without any effort in a hassle-free manner. It should have an easy user interface where, step by step, it would guide you on how to convert OST files into PST format without technical help.
  • Compare the prices and features of the converters so that you avail yourself of the best bargain. There are several options available well within your budget which will be suitable for all your requirements.
  • The trial version can be obtained and tested before purchasing it so as to get acquainted with it in case it fails to fulfill your requirements. Furthermore, back up any sensitive data for extra safety against unexpected issues during the process.

Final words

OST to PST converter software is a helpful utility for all those users who want to convert their OST files in a more comfortable and accessible format, the PST file. With this kind of software, you can access your emails and other important data even when offline.

This kind of software helps in archiving the old OSTs and even shares the same with others on various devices at any point in time. This versatile solution can aid anyone who needs easy conversion between their Outlook formats quickly and safely – providing peace of mind over current usage security and long-term storage options without compromising its safety formulas.

I hope the above details about some of the best converters in the market and other relevant information will help you shortlist one for your purpose.

Next up, top PST migration tools for your office migration.

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  • Satish Shethi
    Satish has been in the IT industry for more than 20 years. He has served a Fortune 100 company as a project manager, looking after US Banking, BFS, Mortgage, Insurance, and FMCG projects. Apart from IT, he enjoys reading books, especially spirituality…
  • Joy R Bhamre

    Joy R Bhamre is a multifaceted professional, holding the title of Editor at Geekflare. She is a Google-certified Digital Marketing Specialist, a seasoned Editor and writer, and a Cambridge-certified English Language Trainer, boasting…

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