SysInfo OST Viewer Tool
Open and view Outlook OST files without Microsoft Outlook or Exchange. Preview emails, contacts, calendars, attachments, and metadata, inspect orphaned files, and export mailbox data easily.
About
SysInfo OST Viewer Tool helps users open, read, and inspect Outlook OST and PST files without requiring Microsoft Outlook, Exchange, or an active Microsoft 365 profile. It supports healthy, corrupted, orphaned, oversized, and password-protected files created by different Outlook and Exchange versions. Users can load individual or multiple files for offline viewing. The software displays mailbox data in a tree structure and provides six preview tabs: Body, Attachments, Notes, Header, MIME, and Raw HTML. Users can inspect emails, contacts, calendars, tasks, notes, attachments, and mailbox metadata. The preview supports up to 20,000 emails in a folder at once. A Smart Search feature helps locate messages using From, To, Subject, date range, and attachment filters. The tool exports mailbox emails to PST, EML, PDF, MSG, CSV, and MBOX formats. It also supports migration to Office 365. Users can apply date filters, remove duplicate emails, skip previously exported items, and resume interrupted exports. Attachment options include keeping, extracting separately, excluding, or saving attachments as pages. Custom folder names and destination paths help organize exported data. The software performs read-only viewing without overwriting original files and supports ANSI and Unicode formats. It is compatible with Windows, macOS, and Linux. Supported Outlook versions range from Outlook 2000 to 2024, including Microsoft 365 environments. The free demo allows users to preview mailbox data and export up to 100 emails per folder. Available editions include Single, Admin, Technician, and Enterprise. To use the tool, add OST or PST files, scan and preview mailbox folders, select an export format, apply filters, choose a destination, and start the process.