Eliminating PST Files: Discovery, Migration, and User Impact

Introduction

For decades, PST files (Personal Storage Tables) have been used to store Outlook emails locally on user devices. While convenient, they create significant compliance, security, and operational risks. Organizations modernizing their email archiving must prioritize the discovery, migration, and elimination of PST files. This blog explores why PST files are problematic and how to phase them out effectively.

Why PST Files Are a Problem

• Compliance Risks: PST files often sit outside centralized retention and legal hold policies.
• Data Loss & Corruption: Files stored locally are prone to corruption and accidental deletion.
• Security Gaps: PSTs on laptops or personal devices create risks of data leakage.
• User Inefficiency: Managing multiple PSTs reduces productivity and complicates searches.
• eDiscovery Challenges: Scattered PSTs make defensible collection and review nearly impossible.

Step 1: Discovery

• Network Scans: Use tools to locate PST files across endpoints, file shares, and NAS systems.
• Inventory Creation: Catalog PSTs by owner, size, age, and location.
• Prioritization: Focus on active users and high-risk PSTs first.

Step 2: Migration

• Automated Tools: Use migration software to extract and ingest PST data into centralized archives.
• Direct Ingestion: Consolidate PST contents into enterprise archives or compliance repositories.
• Batch Scheduling: Migrate PSTs in phases to reduce network strain.
• Maintain Chain of Custody: Ensure defensibility by logging all actions during migration.

Step 3: User Impact

• Communication: Inform employees about the transition and benefits of PST elimination.
• Training: Guide users on accessing historical emails post-migration.
• Mailbox & Archive Quotas: Ensure sufficient storage for migrated content.
• Support: Provide helpdesk resources to handle user concerns and issues.

Best Practices

1. Centralize Archives: Eliminate local PSTs by consolidating into enterprise archives.
2. Automate Migration: Reduce errors by relying on enterprise-grade migration tools.
3. Apply Retention Policies: Ensure migrated data aligns with corporate retention schedules.
4. Monitor Progress: Track migration success and flag incomplete or corrupted PSTs.
5. Decommission PST Creation: Disable the ability to create new PST files.

Compliance Considerations

• SEC/FINRA: PSTs outside of centralized systems may fail to meet retention and immutability requirements.
• GDPR/CCPA: PSTs complicate subject access requests (DSARs).
• HIPAA: Storing PHI in unsecured PSTs creates compliance gaps.

Conclusion

Eliminating PST files is essential for modern email governance. By systematically discovering, migrating, and decommissioning PSTs, organizations can reduce compliance risks, improve security, and enhance user productivity. A well-executed PST elimination strategy creates defensibility, efficiency, and resilience in enterprise email management.