At Target Integration, we’ve managed hundreds of Microsoft 365 migrations, and we’ve learned that the technical migration is only half the story. The real success of any migration depends on comprehensive testing and verification—which is why we’ve built it into every migration project we deliver.
Our Structured Migration Approach
We’ve refined our migration methodology over years of experience to minimise disruption whilst maximising data integrity for our clients.
Phase One: Initial Data Transfer
We coordinate with your organisation to establish a cut-off date, then migrate all emails, contacts, and calendar entries up to that specific point. This creates a complete snapshot of your mailbox environment as it existed at that moment. Our team carefully schedules this to ensure minimal impact on your daily operations.
Phase Two: The Testing Window—Where Your Role Is Critical
This is where we need your active participation. Following our initial migration, we ask users to thoroughly validate their data against the cut-off date. While our automated tools check for technical integrity, only you know what should be in your mailbox. This phase identifies any discrepancies before we complete the final switchover.
We cannot stress enough: this phase cannot be rushed. It’s your opportunity to catch issues whilst we still have time to resolve them.
Phase Three: Final Switchover and Go-Live
Once you’ve completed testing and our team has resolved any flagged issues, we switch your organisation to Microsoft 365 as the primary mail service. We update DNS and MX records, and Outlook becomes your main email platform across all devices.
Why We Build Testing Into Every Migration
Even with enterprise-grade migration tools and our experienced team, large-scale data transfers can encounter issues. We’ve seen organisations lose productivity for weeks because testing was inadequate. That’s why we insist on this phase.
Our testing protocol ensures that:
- All emails and folders transfer correctly, including those in custom hierarchies you’ve built over years
- Contacts and distribution lists remain intact, preserving your communication networks
- Calendar events migrate completely, including recurring meetings, reminders, and attendees
- Folder structures maintain their organisational logic
- Email rules and signatures transfer appropriately (where applicable)
When you identify issues during testing, we can resolve them quickly using our backup systems and remediation tools. Attempting to reconstruct missing data after go-live is exponentially more difficult and disruptive.
What We Need You to Check: A Side-by-Side Comparison
We provide this comparison guide to help you conduct effective testing:
| Feature/Item | Previous Mailbox | Microsoft 365 (After Our Migration) |
|---|---|---|
| Emails | All emails up to cut-off date | Should match exactly across all folders |
| Folders | Custom folders and hierarchical structure | All folders intact with same structure |
| Contacts | All contacts and distribution lists | All contacts present with accurate details |
| Calendar Entries | All events and recurring meetings | All events with correct times and attendees |
| Access Method | Old provider’s interface | Outlook via Microsoft 365 (web, desktop, mobile) |
| Support | Old system IT support | Target Integration project team |
Your Testing Checklist: What We Ask You to Verify
Before we complete the migration, please systematically verify your mailbox using this checklist:
| Item | Verified (✓) | Notes |
|---|---|---|
| All emails migrated correctly | ☐ | Check across all folders, not just Inbox |
| Folder structure intact | ☐ | Verify custom folders and subfolders |
| Contacts visible and accurate | ☐ | Check individual contacts and groups |
| Calendar entries complete | ☐ | Include past and future appointments |
| Recurring meetings present | ☐ | Verify series and exceptions |
| Sent items preserved | ☐ | Important for reference and compliance |
| Deleted items transferred | ☐ | If required by your organisation |
How to Conduct Your Verification
Checking Your Emails: Log into Outlook and systematically browse through all folders. Don’t just check that folders exist—open them and verify emails are present and dated correctly relative to the cut-off date.
Verifying Your Contacts: Review all entries in the People or Contacts section. Check that details (email addresses, phone numbers, custom fields) have transferred accurately. Verify contact groups and distribution lists separately.
Validating Your Calendar: Check all scheduled events, paying special attention to recurring meetings. Verify that invitations include all attendees and that resources (meeting rooms) are still associated with appointments.
How to Report Issues to Our Team
If you discover any discrepancies during testing, contact your Target Integration project team immediately. To help us resolve issues quickly, please provide:
- What is missing or incorrect? (e.g., “Emails from the Marketing folder dated 1-15 March are missing”)
- When did you last see the item? (Reference the cut-off date)
- How critical is the missing data? (This helps us prioritise)
We have backup systems and remediation tools available to address most issues—but we can only help if we know what needs attention. Individual mailbox migrations can occasionally encounter unique issues, so please don’t assume problems are universal.
Completing Your Migration with Target Integration
Once you’ve validated your mailbox, notify your TI project manager that testing is complete. This feedback allows us to track progress across your organisation and ensure everyone is ready for final switchover.
Our Microsoft Services team will then:
- Update DNS and MX records to point to Microsoft 365
- Perform any final delta migrations (capturing emails after the initial cut-off)
- Officially switch over to Outlook as your primary mail service
- Decommission access to the old system according to our agreed timeline
From this point forward, all new emails arrive directly in Microsoft 365.
Our Commitment to Your Success
At Target Integration, we’ve built our reputation on delivering seamless migrations. The testing phase isn’t an administrative formality—it’s our quality assurance checkpoint and your guarantee that years of correspondence, contacts, and calendar commitments make the journey intact.
We’ve learned through experience that successful migrations are built on clear communication and collaboration between our technical team and your users. That’s why we’re here to support you throughout the process. Don’t hesitate to reach out with questions or concerns.
Your diligent testing doesn’t just protect your own data—it contributes to a smooth transition for your entire organisation. The time invested in proper verification pays dividends in productivity, data integrity, and peace of mind once you’re fully operational on Microsoft 365.
Ready to migrate or have questions about the process? Contact the Target Integration Microsoft Services team today.
