Yes, in many situations you can still access the information stored in a PST file even when the original Outlook profile is no longer available. A PST is essentially a local Outlook data file, so losing access to the old Outlook installation does not automatically mean that the information inside the file is inaccessible.

This situation is fairly common when an employee changes computers, an old Outlook profile is removed, or an organization retains mailbox archives after an employee leaves. The PST may still contain years of emails, contacts, appointments, tasks, notes, and attachments.

The first thing I would check is whether the PST is a healthy or orphaned file. An orphaned PST may no longer be connected to an Outlook profile, but the underlying mailbox data can still be present. You should also identify whether the file is ANSI or Unicode because older Outlook versions used different PST formats.

Another consideration is the type of information you need. If you are investigating an old mailbox, simply seeing the email subject line may not be enough. You may need to examine the sender, recipient, timestamps, attachments, message headers, or even the HTML/MIME content. For legal or compliance-related reviews, these details can be particularly important.

A standalone PST viewer can be useful in this situation because it allows the file to be examined without rebuilding the original Outlook environment. For example, SysInfo PST Viewer  supports ANSI and Unicode PST files and can display emails, contacts, calendars, tasks, notes, journals, attachments, and other mailbox components without requiring Microsoft Outlook to be installed.

Search functionality can also save considerable time. Instead of manually opening hundreds of folders, you can narrow the mailbox using criteria such as From, To, Subject, date range, or messages containing attachments. The tool's documentation also describes viewing message headers, MIME, HTML, and other email details.

For sensitive archives, I would also avoid working directly on the original file whenever possible. SysInfo states that its PST viewing operations are read-only by default and that the original PST is not overwritten during scanning or viewing.

So, if the Outlook profile is gone but the PST file remains, there is no immediate reason to assume the mailbox data is lost. The important part is using a method that can recognize the PST format, inspect its contents, and let you locate the information you actually need.