Migrate from PSTs to Microsolves Immutable Email Archive

Data Management Business Practices

Why Email Archiving is a Business Imperative

Dale Jenkins | July 23, 2025

5:51

Let's start with a little history and a file type that most people are familiar with - PST's!

Personal Storage Table (PST) files have been a staple of Microsoft Outlook since the mid-1990s (and the bane of every IT tech for about as long). These files were designed to allow users to offload emails from (often) overloaded mail servers, bypass mailbox quotas and store messages locally for offline access (when dial-up was a thing).

This approach made sense in an era where server storage was expensive and slow internet connections were the norm. Thankfully, the world has changed dramatically since then, however, PST's are still haunting us all!

PST Files: Limitations and Risks

Despite their longevity, PST files are now a liability for businesses the world over. Here’s why:

Corruption and Data Loss: PSTs are notoriously prone to corruption, especially as they grow in size (Microsoft refuse to provide support if they grow over 2GB in size!) or are accessed over networks. PST files routinely become unreadable - often resulting in permanent data loss.
Compliance Nightmares: PSTs are generally stored in scattered, hard to track locations (like personal folders, temp directories or even on USB thumb drives). They often contain sensitive or regulated data, or even email from previous privileged staff members. The contents of a PST file is virtually invisible to compliance tools, making eDiscovery and legal holds nearly impossible without significant effort and expense.
Security Risks: PSTs can be easily copied, lost, stolen or even worse, uploaded to public file services. Even password-protected files are vulnerable to hacking, as demonstrated in a number of high-profile breaches.
Operational Overhead: Managing, backing up, and restoring PSTs is time-consuming and unreliable. Due to their internal structure and large size they are rarely included in regular backups, and restoring them is a manual, error-prone and VERY time-consuming process.
Storage Bloat: Multiple copies of the same PSTs often exist across devices, consuming excessive storage and increasing risk. Further, PSTs are not able to de-duplicate individual email messages likely resulting in multiple copies of the same message existing in different PST files.

PST's are a Data Exfiltration Risk!

Long-Term Email Storage Options

Like any form of digital content, there are multiple options available to manage the data contained within a PST. A PST file should be thought of as a "wrapper" - it's actually the contents of the file that contain the value, rather than the file itself. Lets explore the options and the pros and cons that need consideration:

Option	Pros	Cons
PST Files on local or External Storage	Simple to set up. No additional software or infrastructure required.	High risk of corruption and data loss. Not searchable or indexed centrally. No compliance or retention controls. Difficult to back up and restore.
PST Files on File Servers or Network Drives	Centralises storage compared to local drives. Easier to back up than individual desktops.	PSTs are prone to corruption when accessed over a network. No indexing or search capabilities. Compliance and security risks remain. Slow down backup systems and increase backup costs. Not supported by Microsoft. Increased risk of data loss
PST Files on DVDs or Offline Media	Physical separation from network threats. Low ongoing storage cost.	Media degradation and obsolescence. No search, indexing, or compliance features. Manual retrieval is slow and unreliable.
On-Premises Email Archiving Solutions	Centralised, indexed, and searchable storage. Can enforce retention and compliance policies. Faster eDiscovery.	Requires significant upfront investment and ongoing maintenance. Scalability limited by local infrastructure. Data resilience issues when co-located with primary servers.
Cloud-Based, Immutable, Indexed Email Archiving	Emails are encrypted, indexed, and stored in an immutable (unchangeable) archive. Grows with your business—no storage limits. Fast, comprehensive search and eDiscovery. Simplifies compliance and legal discovery. No more PSTs, slow searching, or missing emails. Offloads storage and management overhead to the provider.	Ongoing subscription cost. Requires trust in the provider’s security and uptime.

Explore the Difference between an Email Backup & an Archive

Why Immutable, Online, Indexed Archiving Is the Best Option

Business email demands more than just the storage that PSTs can offer—it demands security, compliance, accessibility, and scalability.

An immutable, online, indexed, and searchable email archive, like the solution from Microsolve, is purpose-built for these needs:

Immutable Storage: Emails are captured before they reach your inbox, encrypted, indexed, de-duplicated, and stored in an unchangeable archive in the AWS Melbourne cloud. This ensures data integrity and compliance with legal and regulatory requirements.
Effortless Search and Discovery: No more slow searching or missing emails. Advanced indexing means you can find any message, attachment, or conversation instantly, supporting eDiscovery and audit needs.
Compliance and Security: The archive is tamper-proof, supporting legal holds, retention policies, and audit trails. Encryption and cloud storage protect against loss, theft, or disaster.
Scalability: The solution grows with your business—no more worrying about mailbox quotas, storage limits, or manual archiving.
Operational Simplicity: Offloads the burden of email management from IT, freeing up resources and reducing risk.

“Our email archive platform takes a copy of all email messages BEFORE they even reach your inbox, encrypts, indexes, de-duplicates them, and stores them in an immutable (un-changeable!) archive within the AWS cloud.”

Recommendation

If your business still relies on PSTs for long-term email storage, it’s time to move forward. An immutable, online, indexed, and searchable email archive is the only option that truly meets the demands of compliance, security, and business continuity.

Solutions like Microsolve’s not only eliminate the risks of legacy storage but also empower your business to grow, adapt, and thrive.