eDiscovery Software | eDiscovery Collection Software | Pinpoint Labs

PST Regeneration is used during electronic discovery processing or even during an ESI collection.  A Personal Folder File (PST) is a container file created by Microsoft Outlook which stores email messages and other data (i.e. contacts, calendar entries, tasks, to do list etc.)

How it’s done

Regenerating PSTs refers to the identification, isolation and often deduplication of electronic mail (email) messages that pertain to a specific legal matter in civil litigation cases. The filtered email messages are copied to a new “regenerated” PST file. The resulting PST can be considerably smaller than the original and results in the following benefits:

1)      Quicker attorney review

2)      Electronic Discovery processing and hosting cost reduction

3)      Significantly smaller ESI collection

Practical application

PST regeneration is commonly used when there are dozens of archive (backup) PST files that contain many duplicate messages. It is a common practice for companies to set up Microsoft Outlook or Exchange servers to create daily, weekly or monthly PST backups of employee email messages.

The result is potentially dozens of employee backup PST files which contain duplicate messages. Why? Each backup will contain many of the same messages as the last. Only new emails sent or received (that have not been deleted) since the last backup will be considered “unique” to each PST. Regenerating PSTs with only one copy of each email (deduplication) significantly reduces the number of messages and the size of the PST data to be processed or produced.

Maintaining defensibility

Significant cost reductions related to electronic discovery processing and hosting are gained by deduping, performing key word, date range, and email/domain filtering on the emails in PST files. However, it is critical to use an application that is designed to regenerate PSTs in a defensible manner and maintains the chain of custody.

Software such as Harvester from Pinpoint Labs (designed by Certified Computer Examiners (CCE’s)) can regenerate PST files at the point of collection or during in-house processing. Harvester also creates an extensive verification log (chain of custody) for all copied and duplicate messages.

What to remember

Creating deduped, targeted PSTs is common practice in the electronic discovery lifecycle because it saves clients a considerable amount of money as well as reducing attorney review time. PST regeneration may be performed onsite (during an ESI collection) or in-house to cull down responsive data.


This information is provided by Jon Rowe, a Certified Computer Examiner (CCE) and the President of Pinpoint Labs. Please watch the video below to learn more about affordable and defensible tools for E-Discovery collections.