11 Best OST to PST File Converters in 2025


OST to PST file converters are essential tools for anyone using Microsoft Outlook. They allow you to convert OST files into more accessible and flexible PST files.

In this comprehensive guide, we will cover:

• What are OST and PST files?
• Why convert OST to PST?
• 11 best OST to PST converters of 2025
• Key factors to consider when choosing a converter

What are OST and PST Files?

OST (Offline Storage Table) and PST (Personal Storage Table) are two different Outlook data file formats:

• OST files store a local copy of Exchange mailbox data for offline access when not connected to the Exchange server. OSTs synchronize mailbox changes with the Exchange server when connectivity is restored.

• PST files act as personal archives to store Outlook data like emails, contacts, calendars, tasks, etc. PSTs allow users to backup and transfer Outlook data between systems independently of the Exchange server.

While OSTs require constant connectivity to the Exchange server, PSTs give users complete control over their Outlook data offline.

Why Convert OST to PST?

There are several key reasons to convert OST files into the PST format:

• Access OST data offline – PSTs allow full access to Outlook data like emails without requiring connectivity to the Exchange server.

• Migrate OST data – PSTs make it easy to transfer Outlook data when changing email systems or servers.

• Backup OST data – PST files provide a way to backup and archive important OST data.

• Recover corrupted OSTs – Damaged or inaccessible OST files can be recovered by converting to PST.

• Change Outlook configuration – When updating Outlook, converting OSTs to PSTs allows smooth data transfer to the new setup.

• Share Outlook data – PSTs can be easily shared across different systems and users. OSTs have limited sharing capabilities.

• Meet legal requirements – Old email data can be converted to PST format for compliance and eDiscovery purposes.

11 Best OST to PST Converters of 2025

1. Stellar


Stellar is a leading data recovery solution trusted by enterprises worldwide. Their OST to PST converter accurately migrates all Outlook data like emails, calendars, contacts, tasks, notes, etc. from OST files into PST format.

The software supports unlimited OST sizes and maintains original folder structure. It allows saving data in other formats like MSG, EML, HTML, RTF, PDF. Stellar can directly export OST data to Office 365 too.

Key Features:

• Accurate migration of all OST data – emails, attachments, contacts, calendars, tasks, notes, etc.

• Support for latest Outlook 2019, 2016, 2013 versions

• Save OST data in alternate formats like MSG, EML, HTML, RTF, PDF

• No limit on OST file size

• Export OST data directly into Office 365

• Original mailbox structure retained during conversion

• Free trial available

2. SysTools OST to PST Converter


SysTools OST to PST Converter is a fast, automated tool to batch convert multiple OST files into PST format. It can recover and convert OST data after Exchange Server crashes too.

The tool maintains original email formatting and properties during conversion. Users can choose to export only selected OST folders and items if required. Saving OST data directly into Office 365 is also supported.

Key Features:

• Batch convert unlimited OST files into PST format

• Recover OST data after Exchange Server crashes

• Option for selective folder and item export

• Preserves original email formatting and properties

• Save OST data directly into Office 365 accounts

• Free demo available

3. Recovery Toolbox OST to PST Converter


Recovery Toolbox is designed to handle corrupted, password-protected, and encrypted OST files for conversion to PST. It works even without access to the Exchange Server.

The tool can split large PST files into smaller volumes. Users can also export OST data into alternate formats like MSG, EML, VCF, TXT. It tries advanced repairs if ScanOST fails to recover OST data.

Key Features:

• Repair and convert corrupted, encrypted, and password-protected OST files

• Recover OST data without Exchange Server access

• Option to split output PST into smaller volumes

• Save OST data in alternate formats like MSG, EML, VCF, TXT

• Advanced recovery if ScanOST repair fails

• Free trial available

4. OST to PST Converter


OST to PST Converter is an easy-to-use tool to migrate OST files into PST, MSG, EML formats for access across different email clients and platforms.

It can convert even password-protected and encrypted OST files without needing Exchange Server access. The tool also lets you preview OST file content before conversion and select specific items if required.

Key Features:

• Convert OST files into PST, MSG, EML formats

• Handles password-protected and encrypted OST files

• OST to PST conversion without Exchange Server

• Preview OST content before conversion

• Option to selectively convert specific OST items

• Simple user interface

• Free trial available

5. Aryson OST to PST Converter


Aryson builds their OST to PST converter for accurate and secure migration of OST mailbox data into PST and other formats like MSG, EML, MBOX, etc.

It can process bulk OST files in batch mode easily. The tool preserves original folder structure and hierarchy when converting data. OST files can also be exported to Office 365 accounts directly.

Key Features:

• Batch conversion for multiple OST files

• Exports OST data to PST, MSG, EML, MBOX formats

• Direct saving of OST data into Office 365

• Original metadata and hierarchy maintained

• Options for selective folder migration

• Free demo available to convert 50 items

6. MailsDaddy OST to PST Converter


MailsDaddy offers a fast bulk converter to retrieve OST file data like emails, contacts, calendars, tasks, notes, etc. and export to PST, Office 365, and other formats while retaining original structure.

It can process unlimited sized OST files and easily handles password-protected and corrupted OST data. The tool also allows splitting large PST files during conversion for easy management.

Key Features:

• Bulk conversion of unlimited OSTs

• Extracts all OST data – emails, contacts, calendars, tasks, notes, etc.

• Exports OST to PST, Office 365, MSG, EML, MBOX formats

• Split output PST files for easy management

• Repair and convert corrupted, encrypted OST files

• Original folder hierarchy maintained

• Free trial converts 25 items per folder

7. Shoviv OST to PST Converter


Shoviv offers an advanced OST to PST converter with options to save OST data in alternate formats like MSG, EML, HTML, etc. It can recover permanently deleted OST files quickly.

The tool allows setting size limits for output PST files. It also provides an incremental export feature to resume interrupted conversion jobs. The software maintains folder hierarchy and data integrity throughout the process.

Key Features:

• Advanced options to save OST data in alternate formats

• Recovers permanently deleted OST files

• Output PST size limit setting

• Incremental export feature

• Preserves original metadata and folder structure

• Add unlimited OST files for conversion

• Fast batch conversions supported

• Free trial (50 items per folder)

8. Kernel OST to PST Converter


Kernel OST to PST Converter is trusted by IT admins for its ability to thoroughly extract all OST file components including emails, contacts, calendars, tasks, notes, etc.

It uses advanced filters to selectively convert OST data if required. Converted OST files can be exported to formats like PST, EML, MSG, PDF, MBOX, Office docs, etc.

Key Features:

• Selectively export specific OST folders and items

• Advanced filters for selective data conversion

• Exports OST to formats like PST, MSG, EML, PDF, MBOX

• Preserves original OST metadata and folder hierarchy

• Recognizes appointments, meetings, reminders from calendars

• Free demo converts 25 items per folder

9. BitRecover OST to PST Converter


BitRecover builds an OST to PST converter certified by Microsoft MVPs for accurate data migration. It can handle password-protected, encrypted, and orphaned OST files easily.

The tool allows splitting large PST files during conversion. It also provides multi-language support in Dutch, French, German, Spanish and Swedish. BitRecover maintains original attachments and formatting.

Key Features:

• Certified by Microsoft MVPs

• Handles password-protected, encrypted OST files

• Option to split output PST into smaller files

• Maintains original attachment formats and properties

• Multiple international language support

• Converts orphaned OST files without Exchange access

• Free trial available

10. eSoftTools OST to PST Converter


eSoftTools offers an award-winning, heavy-duty OST to PST converter for accurate bulk migration of large OST files. It retains original formatting and structure post-conversion.

The tool can export OST data to Office 365 accounts directly. It also allows splitting large PST files during conversion. Both password-protected and corrupted OST files can be handled easily.

Key Features:

• Bulk conversion of large OST files

• Exports OST data directly into Office 365

• Option to split PST files during conversion

• Handles password-protected and corrupted OSTs

• Preserves original formatting and folder structure

• Ability to preview and select folders before conversion

• Free trial (25 items per folder)

11. KDETools OST to PST Converter


KDETools is a secure, heavy-duty solution for converting OST files into PST, MBOX, MSG, EMLX, Office 365, etc. It facilitates easy migration of complete OST mailbox data.

The batch conversion feature allows fast processing of multiple OST files simultaneously. The tool exports OST contacts and calendar data into individual VCF and ICS formats as well.

Key Features:

• Exports OST into formats like PST, MBOX, MSG, etc.

• Batch conversion feature for multiple OSTs

• Migrate OST data directly into Office 365

• Save contacts and calendar data as VCF and ICS files

• Wizard-based interface for simplified OST migrations

• Original metadata and structure retained during conversion

• Free trial available to preview conversions

Key Factors When Choosing an OST to PST Converter

Here are some important considerations when selecting an OST to PST conversion tool:

• Compatibility – Ensure the tool supports your specific Outlook and OST file versions.

• Conversion Accuracy – The tool must migrate all OST components without any data loss or corruption.

• Preservation of Structure – Original OST folder hierarchy and metadata should remain intact.

• Recoverability – Ability to convert and recover even password-protected, encrypted, and corrupted OST files.

• Selective Conversion – Option to selectively migrate specific OST folders/items when required.

• Alternate Formats – Ability to export OST data into PST, MSG, EML, PDF, MBOX, etc.

• Batch Processing – For fast conversion of multiple large-sized OST files.

• Office 365 Export – Some tools allow direct saving of OST data into Office 365 accounts.

• PST Splitting – Feature to split output PST files into smaller sizes for easy portability.

• Free Trial – Test OST conversion accuracy before purchasing the software.

Conclusion

OST to PST converters provide an efficient way to liberate Outlook data trapped in inaccessible OST files and convert into more useful PST format.

Based on key aspects like conversion accuracy, file recovery, batch processing, alternative format saving, and preserved folder structure – Stellar, SysTools, and Kernel OST to PST converters are my top recommendations.

Carefully assess your specific requirements and choose the best OST to PST migration tool for your needs. With the right converter, you can seamlessly transfer even large volumes of OST data to PST and other formats – saving time while also future-proofing your Outlook email archives.