Law firms rely heavily on email communication. Many times, mailbox archives collect years’ worth of client discussions, case updates, exchanges of evidence, contracts, internal correspondence and court-related information. This information becomes a time-critical challenge to recover and transfer when an email platform is about to close down.
In this case study, we look at how a mid-sized legal firm was able to recover access to hundreds of gigabytes of critical Outlook email archives before their legacy platform was decommissioned. The organization needed a reliable way to convert its legacy PST data to MBOX format while preserving folder structure and not missing important attachments.
The Challenge: Looming Platform Shutdown and Dispersed PST Archives
The law firm had been using Microsoft Outlook for a decade. A large number of PST archives had been accumulated over time from ex-employees, retired partners and closed case departments.
The legal operations department learned that many historical emails would soon be hard to access when the firm’s IT team announced a move away from its current Outlook-based environment. Access to the long-term archive was to be provided through an MBOX-compatible email platform.
The biggest concern was not just the file conversion. The legal teams had to keep the files of cases organized and be able to access past correspondence at a moment's notice.
The migration had to be finished before the platform shutdown was scheduled.
The Client Story: Racing Against a Tight Five-Day Migration Window
The firm represented clients in corporate litigation, employment disputes, property matters, and commercial contracts. Its email archives contained years of correspondence on open and closed matters.
The IT department initially thought the migration would be simple. A more detailed look confirmed that the email data was spread out across multiple PST files created by various employees and departments.
Some of the files were from former partners, some were departmental archives of years of communication with clients.
The team realized that the old environment was not a sustainable option for the long term, which increased the urgency. They wanted to be able to access the archived emails themselves once the platform was shut down.
Their migration requirements were straightforward but critical:
· Export large PST Archives to MBOX format
· Retain the existing folder and subfolder hierarchy
· Retain message details and email attachments
· Multiple PST files batch processing
· Avoid reliance on Microsoft Outlook
· Develop accessible archives for the new email environment
· Finish the project before the shutdown date
Project Overview: Key Data Migration Metrics
In the project there was a lot of historical email data.
Migration Metric | Project Data |
Total PST data | 420 GB |
Number of PST files | 215 |
Estimated e-mail messages | 1.85 million |
Practice departments | 8 active |
Historical archive duration | 12 years |
Largest single PST | 18.6 GB |
Attachments included | Some 340,000 |
Migration opportunity window | Open 5 days |
Given the size and volume of the archives, this was a difficult task to handle manually.
Why Manual PST to MBOX Conversion Failed to Scale
The IT team explored manual methods before settling on a dedicated solution.
Their first option was to try to open PST files one by one via Outlook and try to get the mailbox contents into folders that could then be imported into the target environment.
This approach soon became impractical.
It was a lot of work to manually open and process one PST file at a time. With 215 PST files, the team had to repeatedly attach archives, select folders, export data, check the output and move on to the next file.
Another problem was maintaining the original folder hierarchy in each archive. Legal email data is often organized by client, case number, department or matter. If you put a folder in the wrong place, it may be hard to locate past correspondence later.
The manual method also left ambiguity around attachments and message metadata. The team wanted to avoid having to go through the thousands of emails individually and check them after the export.
They tried out the process with a few archives and then decided that manual conversion was too slow and difficult to scale within the five-day migration window.
They wanted something automated.
The Solution: Bulk Converting PST to MBOX Without Outlook
The firm opted for TrustVare PST to MBOX Converter to perform the bulk conversion project.
The software allowed the IT team to load many PST files at a time instead of processing each archive one by one. This significantly reduced the repetitive effort involved in the migration process.
One of the first benefits of this instrument was the ability to scan and preview mailbox content before conversion. The team was able to preview folders and inspect the data within selected PST archives prior to generating the final MBOX output.
The conversion was also done without the need for Microsoft Outlook installation which provided more flexibility to the technical team while working with archived PST files.
The solution supported different types of PST files including ANSI, Unicode, password-protected, and encrypted files. This helped because the firm had archives from many years using different versions of Outlook.
Most importantly, the conversion preserved the original folder and subfolder structure. This helped to sustain the organizational structure that lawyers and support staff had been using for years.
The team chose the preferred destination, initiated the conversion and monitored the migration process through generated log information.
Key Features That Made the Migration a Success
There were a number of capabilities that made the software especially useful for this urgent migration project.
Bulk PST File Handling
The team could manage multiple PST files rather than continuously processing individual archives. This was necessary to process 215 files in a limited time.
Folder Structure Preservation
One of the firm’s highest priorities was to maintain case-related folder organization. The ability to preserve the existing hierarchy helped to make sure that converted archives were recognizable and easier to navigate.
Email and Attachment Preservation
Contracts, notices, evidence and other important attachments are often part of legal letters. The conversion preserved the content of the emails and related information, reducing concerns about incomplete archives.
Preview Before Converting
The IT team could use the preview capability to inspect the content of the mailbox before starting the export process. This provided an additional validation step for key case files.
No Dependency on Outlook
The team did not need to have an active Outlook installation to process any archive. That made the technical setup easier during migration.
Supports Large PST Files
File size was a major consideration, considering the presence of multiple large archives. The solution enabled the team to process PST files of varying sizes without having to unnecessarily break the project into stages.
Final Results, User Ratings, and Key Takeaways
Migration was performed within the available shutdown window. The law firm successfully converted its 420 GB collection of PST archives into accessible MBOX files and transitioned to its new archive environment before the shutdown deadline.
What the team particularly liked was the combination of bulk processing, keeping the folder hierarchy, the preview function and a simple workflow.
The firm’s IT migration team rated the overall experience, once the project was completed as: 9.4 / 10
They scored well for ease of use, bulk file processing and retention of mailbox organization.
The project also taught the firm a practical lesson:
“Waiting until the last days before a platform shutdown can create unnecessary pressure. Access to the original environment will be limited so historical email archives should be reviewed and migrated well in advance.”
