Migrating to Microsoft 365 (formerly Office 365) is an essential move for modern organisations that want better collaboration, accessibility, and compliance. However, when it comes to migrating legacy email data located in PST (Personal Storage Table) files, many IT administrators are tempted to do it manually – via drag-and-drop, PowerShell scripts, or Outlook Import/Export functions.
While they seem like less expensive options on the surface, they frequently come with unforeseen technical, operational, and financial costs that can kill IT projects and deplete resources.
This post will help you with five significant hidden costs of manual PST migrations to Office 365, and how you can proactively avoid them with a professional migration solution like Kernel PST to Office 365 Migration Tool.
1. High Risk of Data Corruption and Loss
PST files are fragile. Most PSTs were designed for personal use, with the versions before Outlook 2010 not intended for enterprise-level migrations.
Why does this happen?
- File Sizes: Legacy ANSI PST files maxed out at 2GB, while Unicode PST can be much larger. Either way, larger PST files have a higher chance of being corrupted while being copied or uploaded.
- Locked files: If PSTs are still being used or opened by another process, a manual import may fail or partially import records.
- Unsupported items: Custom forms, corrupted items, or non-standard MAPI properties may result in hastily moving old content.
Hidden cost:
- Time wasted trying to fix corrupted PSTs
- The added cost of data recovery tools or services
- Loss of emails that could be critical (legal or compliance)
How to avoid it:
Use an automated PST migration process that checks for data integrity, allows you to work with large files, starts a migration and completes it without you having to manage any files.
2. Time-Intensive and Labour-Heavy Process
Manual migration methods are non-scalable. They may work for a few users, but for hundreds or thousands of PST files across multiple endpoints, the overhead is enormous.
Manual migration approaches scale poorly. They can manage a limited number of users, but over many users, with potentially hundreds or thousands of PSTs across many devices, this approach might not be feasible.
Time-consuming steps include:
- Finding PST files across multiple users
- Granting permissions and creating import jobs via PowerShell or Admin Centre
- Monitoring jobs to determine if they are completed
- Verifying mailbox contents (or user reports) before the old PST contents are deleted
Challenges:
- Human error in scripting (or path mapping)
- Manual re-attempt of failed jobs
- Limited ability to control batch execution and throttling
Hidden cost:
- Operational cost (hours) of the increased project duration
- Loss of IT resources (for many hours) away from their core job functions
How to avoid it:
Automated solutions such as the Kernel Import PST to Office 365 can scan entire networks for PSTs, schedule bulk imports on users’ behalf, and run unattended migration jobs with transparency.
3. Security and Compliance Risks
PST files that are saved locally to desktops, laptops, and shared drives present a significant risk to data governance, which is a critical consideration for heavily regulated industries such as finance or healthcare.
Common security risks:
- No encryption at rest
- No centralised control or audit trail
- The danger of theft, accidental deletion, or ransomware
- No retention or legal hold policies are being implemented
Hidden cost:
- Compliance (e.g., HIPAA, GDPR, FINRA)
- Expensive audits-including penalties
- Reputational damage
How to avoid it:
When PSTs are migrated to Office 365 with a secure migration tool, organisations can:
- Centralise data in Exchange Online
- Implement Information Governance and DLP policies
- Utilise Advanced eDiscovery with audit logging
4. Lack of Granular Control and Customisation
Manual approaches to importing data are usually an all-or-nothing process without much control over the mapping or filtering of the data during migration. Some of the limitations of manual migration are:
What you can’t do with manual migration:
- There is no mapping between the source folder and the target directories.
- You can’t filter by date range, sender, or folder.
- You can’t regulate how duplicates are handled, and you can’t fix conflicts.
- No preview or possibility to import only certain things
Hidden cost:
- Wasted mailbox space due to redundant or duplicate data
- User confusion regarding mismatched folders or content
- Extra work post-migration.
5. Unreliable Monitoring and Reporting
Manual migrations typically provide little visibility. When something fails, the first time admins even know about it, users may be complaining, or worse.
Weaknesses include:
- No centralised dashboard for tracking multiple migration jobs
- Limited error logs or diagnostic information
- No automated alerts for failed PSTs or throttled mailbox imports
Hidden cost:
- It can be challenging to identify and correct failed jobs
- Missed SLAs or project deadlines
How to avoid it:
Automated PST migration tools offer:
- Detailed logs for each file and mailbox
- Centralised reporting dashboards
- Status alerts and options for auto-retries
- Exportable/printable reports for documentation
Solution: Use a Professional Tool
To avoid the hidden costs and optimise the whole PST migration life-cycle, organisations should choose an enterprise-grade tool for this purpose, such as Kernel Import PST to Office 365.
Technical Features:
- Import directly to Office 365 mailboxes, archive mailboxes, or shared mailboxes
- Centralised PST file scanning across the network from unlimited systems
- Batch import using CSV mapping
- Modern Authentication support (OAuth 2.0) & MFA support
- Incremental import to skip already imported items
- Date, folder, and item-type filters for a custom migration
- Reporting and logging for audit and compliance
Business Benefits:
- Migrate faster
- Higher accuracy and completeness of data migrated
- Less interruption to the end-user
- Protect against future compliance risk from PST files
Final Thoughts
Manual PST migration to Office 365 might look like a low-cost option, but the costs can easily add up and surpass any savings. Loss of data, compliance risks, and pushing your IT staff to move data, plus creating documentation, are just some of the many impacts when you go manual.
Professional PST migration tools such as Kernel Import PST to Office 365 provide a very smooth, safe, compliant, and scalable method for PST migration.
If your business is planning a PST to Office 365 migration plan, don’t go manual – go smart!
