OST Converter Tool (2026 Enterprise Edition) Frequently Asked Questions

Add your .ost file, choose PST (Unicode) and click Convert. Full steps: Convert an OST file to PST

Yes. Prism OST Converter uses direct block-level B-Tree parsing rather than relying on Windows Outlook APIs. It reads around damaged sections where possible. For corrupted or password-protected OST files, test your own file in the free trial.

Yes. The software uses a streaming chunked buffer (64KB chunks) that iterates through mailbox records sequentially. Because it never attempts to load the entire 50GB file into system RAM, it reads large archives in chunks. Test your own file in the free trial.

Select PDF in Step 4. Prism OST Converter formats each email with standardized sender headers, date stamps, and message bodies. Crucially, email attachments are embedded directly as physical binary files inside the PDF container, satisfying legal eDiscovery and Bates numbering compliance.

Prism OST Converter logs every processed item in an embedded SQLite ACID transaction journal (prism_ost_checkpoint.db). If your system restarts or network drops, simply relaunch the software and click Resume. The engine continues from where it stopped.

Yes. Prism OST Converter is built as a Universal Binary supporting macOS 15 Sequoia, Sonoma, Ventura, and Monterey natively on Apple Silicon (M1, M2, M3, and M4) as well as Intel x86_64 processors without requiring Rosetta emulation.

Yes. Select Microsoft 365 as your output destination. Enter your Microsoft 365 admin or user credentials via modern OAuth 2.0 PKCE. The tool uses Microsoft Graph API to upload emails, folders, contacts, and calendar entries directly into primary inboxes or online archive mailboxes.

Outlook ties an .ost file to the profile that created it, so it can refuse to open after the profile changes. You can read the file with Prism OST Converter and save the data as a PST. Steps

Yes. The conversion engine decodes MIME multipart attachments, nested message attachments, inline CID images, and rich HTML styles.

Yes. In Step 3 (The Filter Engine), you can configure inclusive start and end dates, filter by sender/recipient email addresses or wildcard domains, and search for specific subject keywords. Only emails matching your criteria will be converted, making it easy to create a targeted offline backup.

The free trial allows converting up to 50 items per folder in the available export formats, giving you complete visibility into folder structures, message bodies, and attachments before purchasing a license.

By default in C:\Users\<YourUsername>\AppData\Local\Microsoft\Outlook\. How to open that folder

Following successful payment, your digital license key is delivered to your billing email address. If you need your key resent or require assistance with activation, you can contact our team anytime via our Contact Support page.

We provide free evaluation versions for all tools so you can test compatibility and conversion fidelity on your own data before buying. If you encounter a verified technical limitation or defect that our engineering support team cannot resolve, purchases are covered under the terms detailed on our Refund Policy page.