SysInfo PST Viewer is a standalone utility for opening and viewing Outlook PST files without installing Microsoft Outlook. It supports healthy, corrupted, orphaned, empty, oversized, and password-protected PST files. Users can load single or multiple PST files and inspect mailbox data without altering the original file. Scanning and viewing are read-only by default, and the software operates offline without uploading mailbox data to the cloud. Preview emails, attachments, contacts, calendars, tasks, notes, drafts, journals, RSS feeds, and conversation settings. Email details include sender, recipient, subject, body, headers, MIME information, and raw HTML. Browse the original folder hierarchy and view up to 20,000 emails in the preview panel at a time. Search for messages by From, To, Subject, date range, or attachment status. Export filters can include or exclude specified To, From, and Subject values. Duplicate emails can be detected using To, From, Subject, Body, and CC. Date-based filtering supports selective export. Attachment options include keeping files with emails, placing them on separate document pages, extracting them to a folder, or excluding them. Export PST data to PST, EML, MSG, MBOX, PDF, or CSV, or import PST files into Office 365. Create individual or merged PDFs, split large PST exports by size, and use Skip and Resume if an export is interrupted. Office 365 export supports folder hierarchy retention or mailbox mapping. Progress details and export logs are available. The viewer supports ANSI and UNICODE PST files from Outlook 97–2002 through Outlook 2024 (LTSC). The product overview lists Windows, Mac, and Linux availability; consult the system requirements for supported operating-system versions. Version 26.6 is listed at 220 MB, released 9 June 2026. Editions are Single, Admin, Technician, and Enterprise. The demo allows viewing, backup, and conversion of up to 100 PST emails per folder; unlimited conversions require a licence. Offline mode.