PST migration to Microsoft 365 and Exchange
PST files have long been used to store historic Microsoft Outlook email, but managing large collections of PST files can create significant challenges for organisations. Files may be scattered across laptops, desktops, network drives and file servers, making them difficult to discover, secure and manage centrally.
Ultimate Migrator provides specialist PST migration software to help organisations discover, analyse and migrate PST files into Microsoft 365, Microsoft Exchange and other supported destinations. Our technology automates PST discovery, identifies file ownership and manages migration at scale, with centralised reporting and error handling throughout the process.
The issues with PST files
Organisations maintaining large PST estates face several challenges, including data security, regulatory compliance, storage costs and limited access to historic email. Migrating PST files into a centrally managed environment can help address these issues:
Data security and compliance risks
Consolidating historic email into a centrally managed platform helps organisations improve information governance, support regulatory compliance and reduce the risk of data loss.
High storage and management costs
Migrating PST files into Microsoft 365, Microsoft Exchange or another supported destination helps organisations consolidate historic email, reduce unnecessary storage duplication and simplify ongoing administration.
Data corruption and loss risks
Ultimate Migrator identifies problematic PST files during discovery and provides error handling, retry management and detailed reporting during migration. This helps organisations maximise successful migration while identifying exceptions that require investigation.
Limited access to historic email
Migrating PST files into Microsoft 365, Microsoft Exchange or another centrally managed platform helps organisations make historic email more accessible, searchable and manageable, while reducing reliance on individual devices and legacy storage.
Automated PST migration software
Our automated approach reduces the manual effort associated with large-scale PST migration projects. From locating files and identifying their owners through to scheduling migrations, managing errors and reporting on progress, Ultimate Migrator provides centralised control throughout the process.
Organisations can consolidate historic email, improve information governance and reduce their dependence on unmanaged PST files, while maintaining visibility of migration activity and outstanding exceptions.
Automated PST discovery and ownership identification
Automated PST ownership identification
Ultimate Migrator uses advanced algorithms and configurable rules to accurately identify and assign ownership of PST files during discovery. This automated approach reduces the risk of incorrect ownership assignments associated with manual methods.
Accurate PST ownership identification helps organisations ensure historic email is migrated to the correct user mailbox, improving data integrity and reducing manual intervention during large-scale PST migration projects.
Automated PST file discovery
Large organisations may have tens of thousands of PST files scattered across network drives, desktops, laptops and other storage locations. Manually locating and cataloguing these files can be extremely time-consuming and impractical.
Ultimate Migrator automates PST file discovery across an organisation’s IT environment, including workstations and laptops. Configurable discovery settings help identify PST files at scale, reducing manual effort and providing a more complete picture of the organisation’s historic email data.
Distributed PST Discovery Architecture
PST files are often distributed across multiple offices, network locations and geographically dispersed IT environments. Ultimate Migrator’s distributed architecture enables organisations to discover PST files efficiently across these locations, without requiring all data to be consolidated beforehand.
This approach supports faster PST discovery across complex IT environments while minimising disruption to users and day-to-day business operations. It is particularly valuable for organisations managing large PST estates across multiple sites.
Detailed PST discovery reporting
Ultimate Migrator analyses PST files during discovery, collecting essential information including file size, message count, storage location, password protection and potential corruption issues.
Detailed PST discovery reports give organisations a clear understanding of their existing PST estate, helping migration teams assess data volumes, identify problematic files and plan resources effectively. This information supports accurate project planning and helps reduce unexpected issues during large-scale PST migration projects.
Automated and scheduled PST migration
Built-in PST migration connectors
Ultimate Migrator includes built-in connectors that enable PST files to be migrated directly into a wide range of email and archiving platforms, including Microsoft 365, Microsoft Exchange, Mimecast and EV.Cloud.
These connectors streamline PST migration by reducing the need for manual data handling or intermediate migration processes. Organisations can consolidate historic email into their chosen destination while maintaining centralised control over the migration process.
PST migration scheduling and control
Ultimate Migrator provides comprehensive control over PST migration projects through built-in scheduling, batch management and configurable migration settings. Administrators can control which messages are migrated based on criteria such as message type and date.
Detailed progress reporting provides visibility throughout the migration process, helping organisations monitor completed migrations, track outstanding work and manage large-scale PST migration projects efficiently from start to finish.
Intelligent PST migration error handling
Ultimate Migrator incorporates intelligent error recovery and reporting to identify and manage issues during PST migration. Errors and exceptions are flagged promptly, helping migration teams investigate and resolve problems with minimal manual intervention.
This automated approach reduces disruption, improves migration efficiency and provides greater visibility of outstanding issues. Organisations can manage large-scale PST migrations with confidence, knowing that problems are identified and reported throughout the process.
Parallel PST migration processing
Ultimate Migrator uses multi-threaded processing to handle multiple PST migration tasks concurrently, helping organisations migrate large volumes of historic email efficiently.
By making effective use of available processing resources, this approach helps reduce overall migration timescales and associated costs. It is particularly valuable for large-scale PST migration projects involving thousands of files and substantial volumes of email data.
The benefits of automated PST migration
Once PST files have been migrated into a centralised platform such as Microsoft 365, Microsoft Exchange, Mimecast or EV.Cloud, previously scattered and difficult-to-access email data becomes easier to search, manage and protect.
Centralising historic email helps organisations improve information governance, apply consistent security and retention policies, support GDPR compliance and reduce the costs associated with maintaining unmanaged PST files.
Ultimate Migrator provides the discovery, migration controls and reporting needed to support this transition, giving organisations greater visibility of their historic email data and confidence in the migration process.
Complete PST data visibility
Ultimate Migrator provides organisations with a comprehensive overview of their PST file estate, including file locations, ownership, data volumes and potential issues identified during discovery.
Detailed reporting throughout the migration process helps administrators track progress, identify outstanding files and maintain visibility of historic email data as it moves into a centrally managed platform.
Improved PST data security and compliance
Migrating PST files into a centrally managed email or archiving platform helps organisations improve the security of historic email data by reducing reliance on files stored across individual devices and shared drives.
Centralised storage enables organisations to apply consistent access controls, retention policies and information governance procedures. This helps support GDPR compliance, reduce the risk of unauthorised access and improve accountability for sensitive business information.
Reduced PST storage and management costs
Migrating PST files into a centrally managed email or archiving platform helps organisations reduce the costs associated with maintaining scattered PST files across desktops, laptops, network drives and backup systems.
By consolidating historic email and reducing unnecessary data duplication, organisations can simplify storage management, reduce administrative overheads and minimise the ongoing costs of supporting unmanaged PST files.
Automated and auditable PST migration
Ultimate Migrator automates key stages of the PST migration process, reducing manual effort and helping organisations deliver large-scale migration projects efficiently and cost-effectively.
Built-in scheduling, intelligent error handling and comprehensive reporting provide a clear record of migration activity, progress and exceptions. This supports audit requirements, improves project accountability and helps organisations demonstrate that historic email data has been migrated in a controlled and transparent manner.
How our PST migration process works
Step 1: Discover and locate PST files
Discovering PST files is a critical first stage of any successful PST migration project. In medium and large organisations, thousands of PST files may be scattered across servers, network drives, desktops and laptops, often in multiple geographical locations.
Manually locating and cataloguing these files is time-consuming and prone to human error. Ultimate Migrator’s PST Accelerator automates the discovery process using a distributed architecture, enabling PST files to be identified across central and remote locations.
Importantly, PST Accelerator also verifies that discovered files are genuine Microsoft Outlook PST files, rather than simply relying on the .pst file extension. This helps eliminate irrelevant files and ensures that discovery reports provide an accurate picture of the organisation’s PST estate.
The result is a reliable inventory of PST files that supports ownership identification, migration planning and accurate assessment of the data to be migrated.
Step 2: Identify and assign PST file owners
Accurately identifying PST file ownership is essential to ensuring that historic email is migrated to the correct destination mailbox. This can be particularly challenging in large organisations where PST files have been moved, renamed or stored in shared locations.
Ultimate Migrator’s PST Accelerator uses sophisticated algorithms and configurable rules to determine PST file ownership during the discovery process. Multiple factors can be considered to establish the most appropriate owner for each file, reducing the risk of incorrect assignments associated with manual methods.
Automating PST ownership identification helps organisations minimise manual intervention, improve migration accuracy and reduce the risk of historic email being transferred to the wrong user’s mailbox.
Step 3: Schedule and manage PST migration
The final stage involves migrating PST file contents into the chosen destination platform. Ultimate Migrator supports scheduled, multi-threaded PST migration to a range of email and archiving systems, including Microsoft 365, Microsoft Exchange, Enterprise Vault, Mimecast and other supported platforms.
Built-in scheduling and parallel processing help organisations manage large volumes of PST data efficiently, reducing migration timescales and minimising disruption to everyday operations.
Ultimate Migrator is designed to handle common migration challenges, including corrupt messages, network connectivity problems and destination storage limitations. Configurable retry mechanisms, options for skipping problematic items, corruption reporting and quota management help administrators identify and manage exceptions throughout the migration process.
Comprehensive progress and error reporting provides visibility of completed migrations, outstanding tasks and issues requiring attention, helping organisations deliver controlled, auditable PST migration projects.
PST migration, GDPR compliance and Subject Access Requests
Unmanaged PST files can create significant challenges for organisations responding to data subject access requests (DSARs) under the UK General Data Protection Regulation (UK GDPR). When an individual requests access to their personal data, organisations must be able to identify and retrieve relevant information, including personal data contained in historic email archives and PST files.
Although individual PST files can be searched using Microsoft Outlook, manually locating, opening and searching thousands of files across an organisation is time-consuming, resource-intensive and prone to error. This becomes particularly challenging when PST files are scattered across multiple offices, network drives, laptops and legacy storage systems.
The challenge of discovering historic email data
Organisations frequently underestimate the volume of PST data held across their IT environments. In one migration project, an organisation initially estimated that it held between 1 TB and 2 TB of PST files. Ultimate Migrator’s discovery software subsequently identified more than 46.5 TB of PST data.
Without automated PST discovery, organisations risk overlooking significant volumes of historic email when responding to information requests, conducting investigations or planning migration projects.
Supporting Subject Access Requests and eDiscovery
Under UK GDPR, organisations must generally respond to a data subject access request within one month, although extensions may be permitted in certain circumstances. Locating and reviewing relevant information across thousands of unmanaged PST files can make meeting these deadlines particularly challenging.
Migrating PST files into a centrally managed platform such as Microsoft 365, Microsoft Exchange, Mimecast or EV.Cloud can help organisations take advantage of the destination platform’s supported search, retention and eDiscovery capabilities.
Ultimate Migrator helps organisations discover, analyse and migrate historic PST data, reducing reliance on manual searches and improving visibility of information held across the business.
By centralising historic email, organisations can improve information governance, support GDPR compliance and reduce the time and resources required to locate information for Subject Access Requests, legal investigations and regulatory enquiries.