Microsoft Outlook Data Files: A Complete Guide to the OST and PST File Formats

Microsoft Outlook Data Files

Microsoft Outlook, an integral part of the Microsoft Office suite, is one of the most widely used email and personal information management tools. At the heart of this application are two primary data file types: OST (Outlook Offline Storage Table) and PST (Personal Storage Table). This guide aims to provide comprehensive insight into these file types, various aspects related to converting OST to PST, and more. Read on to learn more about these Outlook data files.

Table of Contents

Understanding OST and PST Files

An OST file stands for ‘Offline Storage Table.’ As the name suggests, this file format allows users to work offline and later synchronize their changes with the Exchange Server. OSTs are essentially a mirrored version of a user’s mailbox stored on the Exchange Server. These are especially useful when there’s no internet connection, allowing for uninterrupted work.

PST, or ‘Personal Storage Table,’ is essentially the storage format for all versions of Microsoft Outlook. This file type stores emails, contacts, calendars, and other data. Users can create PSTs to back up their data or to transfer it between different computers.

Why Convert OST to PST?

There are various reasons to consider converting OSTs to PSTs:

  • Data Migration: If you’re switching computers or migrating data, it’s simpler to move PST files than to synchronize OSTs with the Exchange server.
  • Backup Purposes: PST files can serve as backup options for mailbox data, whereas OSTs are more transient in nature.
  • Corrupted OST Files: OSTs, being a reflection of server data, can sometimes become corrupted. Converting them to PSTs can often recover much of the lost data.

How to Convert OST to PST

The process of converting the two formats is not straightforward within Microsoft Outlook. This is primarily due to OST’s synchronization relationship with the Exchange Server. As such, the need arises for third-party OST to PST converter software, although it is possible to convert these files manually.

  1. Manual Method: One way to manually convert .ost to .pst is by using Outlook’s in-built export feature:
    1. Launch Microsoft Outlook and connect it to the OST file you want to convert.
    2. Click on the ‘File’ tab.
    3. Choose ‘Open & Export’ and then ‘Import/Export.’
    4. Opt for ‘Export to a file’ and select ‘Outlook Data File (.pst).’
    5. Follow the on-screen instructions to export OST to PST.
  2. OST to PST Converter Software: Given the complexities and potential risks involved in manual conversion, many users opt for specialized software that can convert .ost to .pst. These tools can automate the conversion process, often offering additional features like bulk conversions, advanced recovery options, and more.

When selecting an OST to PST conversion software, ensure that you choose a reliable and well-reviewed solution. Let’s take a look at how you can select tools to prevent data loss with subpar software.

Selecting the Right OST to PST Converter Software

There’s no shortage of conversion software options in the market, but not all are created equal. Here are a few factors to consider:

  • Integrity Maintenance: Choose software that maintains the integrity of emails, attachments, folders, and metadata during the conversion process.
  • Preview Option: Before initiating the Outlook convert OST to PST, it’s handy to have a preview option to validate the data being converted.
  • Bulk Conversion: If you have multiple OSTs, look for software that offers bulk conversion capabilities.
  • Customer Support: Good software should be backed by responsive customer support for troubleshooting and queries.

Using the search terms “convert .ost to .pst” or “Outlook convert OST to PST” can yield numerous results. Still, always cross-reference user reviews and expert opinions before making a choice.

Safety Precautions

While using third-party software solutions for conversion:

  • Don’t Forget about Backups: Always back up your OSTs before initiating the conversion process.
  • Avoid Free Converters: Free converters might seem tempting, but they often come with limitations and might not be safe. Invest in a reputable tool for your conversion needs.
  • Regularly Update: Ensure you have the latest version of your chosen OST to PST conversion software. Regular updates typically include essential patches and improved features.


Understanding the intricacies of Microsoft Outlook data files, especially when it comes to converting .ost to .pst, is crucial for anyone who relies heavily on this email client. Whether you’re manually exporting or using converter software, it’s essential to approach the process with caution and knowledge. With the right tools and practices, your data migration can be seamless and efficient.

Shashank Sharma
Shashank is a tech expert and writer with over 8 years of experience. His passion for helping people in all aspects of technology shines through his work. He is also the author of the book "iSolution," designed to assist iPhone users. Shashank has completed his master's in business administration, but his heart lies in technology & Gadgets.

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