Our IT department recently started a company-wide mailbox cleanup project after years of employees saving Outlook data in local PST files. The problem wasn't just the number of files—it was the fact that every department had multiple archives, some dating back nearly a decade. Before we could archive or migrate anything, we needed to review the contents without spending days opening each file individually.

I started searching for a PST viewer that could simplify this process, especially one capable of handling multiple PST files at the same time. After trying several options, I tested MacSonik PST Viewer Pro , and it seemed well suited for enterprise mailbox management.

One feature that immediately saved time was the ability to perform bulk PST analysis. Instead of loading archives one by one, we could inspect several PST files simultaneously, making it much easier to compare mailbox contents across different users. The software remained responsive even with large archives, which was important since many of our PST files exceeded the typical mailbox size.

The mailbox preview was comprehensive. Besides emails, we could review contacts, calendars, tasks, drafts, deleted items, notes, and attachments while preserving the complete folder hierarchy. That made it easier to understand where information was stored without changing the original mailbox structure.

For audit requests, the advanced search tools were extremely helpful. Rather than manually scrolling through thousands of emails, we filtered messages using sender, recipient, subject, date range, and attachment criteria. It significantly reduced the amount of time required to locate specific communications during internal reviews.

Another advantage was the detailed metadata inspection. We could verify internet headers, timestamps, sender information, attachment properties, MIME content, and other email attributes directly from the preview window. This proved useful when validating archived communications before exporting selected data.

Since our organization has strict security requirements, I also appreciated that all processing occurred locally. No mailbox information was uploaded to external servers, and every operation generated a detailed activity log, providing a clear audit trail for compliance documentation.

If we needed to move data later, the export options covered nearly every requirement, including PST, PDF, EML, MSG, MBOX, CSV, and direct migration to Microsoft 365.

I'm interested in hearing how other IT administrators handle large collections of Outlook archives. Which a PST viewer has become your go-to solution for enterprise mailbox reviews? Has anyone else used MacSonik PST Viewer Pro for large-scale audit or compliance projects, and how did it perform compared to other tools?