How to Convert PST File into an OST File with All Data

When it comes to managing Outlook data, two important file formats you’ll often encounter are PST (Personal Storage Table) and OST (Offline Storage Table). While PST files are used for storing mailbox data in a portable format, OST files are tied to a specific Outlook profile and allow you to work offline with your Exchange, Office 365, or IMAP account.

Many users search for ways to convert PST to OST—especially when they switch accounts or want to import old emails into a new Outlook profile. However, unlike PST files, OST files are not designed for direct importing. So, the process requires a few careful steps.

In this guide, we’ll explain what PST and OST files are, why someone might want to convert PST to OST, and how you can do it effectively.

What Are PST and OST Files?

PST File (Personal Storage Table)

Stores mailbox items like emails, contacts, calendars, and tasks.

Commonly used for backups or migration.

Can be opened in any Outlook profile.

OST File (Offline Storage Table)

Created when you set up Outlook with Exchange, Office 365, or IMAP accounts.

Allows offline work; syncs automatically when connected to the server.

Linked to a specific Outlook account/profile.

Why Convert PST to OST?

Here are some common reasons why users may want to convert PST into OST format:

1. Migrating Data to a New Account – You may have old PST backups that you want to sync into a new Exchange or Office 365 account.

2. Restoring Mailbox – If you need to restore data from a PST backup into a server-synced account.

3. Accessing Emails Offline – OST allows you to work offline with synced data.

4. Centralized Management – Businesses often prefer OST over PST for server synchronization and better security.

Can You Directly Convert PST to OST?

The short answer is no—Outlook does not provide a direct option to convert PST into OST. OST files are automatically created by Outlook when you configure an Exchange, IMAP, or Office 365 account.

However, you can import PST into Outlook and then let Outlook sync the data with the server. This process effectively converts your PST data into OST.

How to Convert PST File into OST File (With All Data)

Here are the step-by-step methods:

Method 1: Import PST into Outlook and Sync with Server

1. Open Microsoft Outlook.

2. Go to File > Open & Export > Import/Export.

3. Select Import from another program or file and click Next.

4. Choose Outlook Data File (.pst).

5. Browse and select your PST file.

6. Select options for duplicates (replace, allow, or do not import).

7. Choose the folder to import into (e.g., Inbox or entire mailbox).

8. Click Finish.

9. Outlook will sync the imported data with the Exchange/Office 365/IMAP server, creating an updated OST file.

Method 2: Create a New Outlook Profile

1. Close Outlook.

2. Go to Control Panel > Mail > Show Profiles.

3. Click Add and set up your Exchange, Office 365, or IMAP account.

4. Open Outlook with the new profile.

5. Import the PST file using the steps from Method 1.

6. Outlook will generate a fresh OST file and sync it with the server.

Method 3: Use Professional Tools

If you have a large PST file or want a faster automated solution, you can use third-party PST to OST converters. These tools simplify the process by directly migrating PST data into OST or even directly importing PST to Office 365/Exchange accounts.

Some popular tools include:

Kernel for PST to OST Converter

Stellar Converter for OST

SysTools PST to OST Converter

(Always choose a trusted tool to avoid data corruption.)

Tips for Successful Conversion

Backup Your PST File before starting the process.

Ensure Outlook is properly configured with an Exchange/Office 365/IMAP account.

For large PST files, import in smaller chunks to avoid errors.

Use professional software for hassle-free bulk migration.

Final Thoughts

While Outlook doesn’t provide a direct “convert PST to OST” button, you can still achieve the same outcome by importing your PST data into an Outlook profile connected to a server account. This way, the imported data syncs with the server and is stored in a fresh OST file.

For small amounts of data, the manual method works fine. But if you’re dealing with large or multiple PST files, using a professional tool can save you time and prevent potential issues.