The easiest way to view  PST file without having Outlook installed is by using a third-party tool like MSOutlookhelp PST File Viewer. This free software allows you to open and read PST files without needing Microsoft Outlook. The tool can access all data in the PST file, including emails, contacts, calendars, tasks, and attachments. It supports large PST files and can even open multiple files at once.

Moreover, the PST File Viewer provides a simple, user-friendly interface, making it easy for non-technical users to navigate. You can preview your data and save it in other formats, such as PDF, CSV, EML, or MBOX, for easy sharing or archiving. The tool also works independently, meaning you don't need to install or configure Outlook to access your files. This makes it a convenient solution for anyone needing to view PST files without Outlook installed.