PST file migration, consolidation and elimination

What are PSTs and why do I need to migrate?

PST (‘personal storage table’) files are the default format for storing offline messages and other items within Microsoft Exchange Client, Windows Messaging and Outlook. Organizations typically have many thousands of unmonitored PSTs created by users, scattered throughout the enterprise – on desktops, laptops, removable disks and shared drives.

PSTs create management headaches, present security and compliance issues, and are a huge data leakage risk. But most organizations have very little insight into where PSTs are actually created and kept, or how much data is in those files. For example, a confidential employee salary listing could be stored in a PST file – but how would the organization determine whether the file exists, who owns it, where it is located, or who should have access to it?

The solution is to eliminate offline files entirely by migrating and consolidating PST email and associated journal data to more cost-effective platforms such as Office 365 or Exchange 2013, or an archiving solution such as Enterprise Vault (EV).

PST FlightDeck efficiently manages the entire end-to-end migration process by locating PST files, transferring them to a central location, and ingesting them to your platform(s) of choice.

What are the problems with PST files?

PSTs are not centrally managed

There is no way of confirming exactly how many PSTs there are in the infrastructure, where they are, whether they are corrupted, whether they are duplicates or whether the people who created them have left the company. And as messaging has grown, underlying infrastructures have struggled to keep up with storage requirements and have been pushed to extremes through demand for data mobility.

PSTs are inefficient

Although discouraged by Microsoft, organizations often store centralized PST files on NAS and/or file servers; it is not uncommon for them to take up 25 percent of this expensive disk space allocated for users. In a NAS environment the load coming from PSTs is high, as many blocks (small parts of the PST) change on an extremely frequent basis; this also makes backup difficult and costly.

Data loss, corruption and Outlook speed reduction are just some of the symptoms of attempting to centralize PSTs in an enterprise environment. With Outlook 2013 even more corruption can occur as its tolerance for network-based PST files is further reduced.

With thousands of users in your organization the problem multiplies exponentially, and it may be that your IT support staff have to spend disproportionate time simply repairing broken PST files.

PSTs inhibit business-aligned change

Organizations looking to modernize their IT services are constrained by PST files. PSTs are incompatible with – and a blocker to – more modern client architectures involving multiple devices, VDI and BYOD, and need to be tackled as part of any planned migration to cloud services such as Office 365.

PSTs represent a major security risk

Most users can create, copy and move PSTs around easily. The sheer portability of PSTs means they accidentally end up in the wrong places, and they are easily exported by the malicious. Evidence suggests that hackers target unsecured PSTs as they will be known to contain valuable data.

PSTs are an obstacle to legal and compliance requirements

With such a massive amount of duplicated, dispersed information, legal departments struggle to ensure they have the right data to defend cases. Compliance teams are unable to enforce retention policies on data stored on local machines, as it does not get backed up.

The PST migration process

It is essential to plan projects to avoid user disruption, data loss, legal risk and overloading operational resources. PST FlightDeck has all the functionality you need built in to ensure scalable and risk-free PST migration projects.

User considerations

It is important to recognize that PST files are user files. Some may be private, some may no longer be needed, and some may require specific authorization for migration. PST FlightDeck includes flexible options for user communication to ensure the necessary permissions and procedures are followed. PST FlightDeck also distinguishes between power users and others, and makes appropriate checks for rogue PSTs according to their profiles.


For PST files to be processed they must first be centralized. An intelligent agent locates the files, determines ownership and identifies how many there are and how much storage is consumed. PST FlightDeck optimizes bandwidth control during centralization to avoid resource overload and preserve user access without risk of downtime.


After centralization the files must be processed to reconcile users, remove passwords, repair any corruptions and, importantly, to de-duplicate at an item level to reduce storage and avoid user confusion. Shared PST files, and those belonging to users that have left, must also be addressed.

With ‘disconnected’ PST files, there’s no obvious way of knowing what PST is associated with which user. Some vendors use an automated two-factor owner analysis to reconcile files, but PST FlightDeck uses an industry defining six factors: original location, creator, attachment of other PSTs, user directory cross-checking, inspection of content – who most commonly sent and received from that mailbox – and automatic assessment of probable user against expected user. This substantially reduces the amount of operator intervention required.

Ingestion and cleanup

PST FlightDeck’s Advanced Ingestion Protocol (AIP) dramatically shrinks the size of data that actually needs to be ingested into the new environment, so that physical migration takes place much faster. Target platforms typically include Office 365/Exchange Online, Exchange 2013, an on premise or cloud email archive, or any hybrid combination.
After ingestion, PST FlightDeck cleans up shortcuts, safely eliminates old PSTs, and removes safety backup copies after an appropriate amount of time.