While searching for a method to open OST file without Outlook, my main concern was data safety. I didn’t want any tool that could modify or corrupt the original OST file. That’s where the SysInfo OST Viewer stood out. It provides complete read-only access, meaning the original OST file remains unchanged throughout the process. You can freely explore emails, attachments, contacts, and calendars without risking data integrity. This feature is ideal for compliance checks, audits, or simple mailbox verification where preservation of original data is critical. For users who want to safely open OST file without Outlook and ensure zero alteration to mailbox data, this read-only approach is extremely reassuring.