Email is the lifeblood of most businesses, so migrations need to be careful and well communicated.

Common scenarios

– On-premises Exchange to Microsoft 365

– Another email platform (Google, IMAP hosts) to Microsoft 365

– Tenant-to-tenant: merging companies, rebranding, or splitting divisions

Migration methods for email

– Cutover: move all mailboxes at once. Suited to small organizations.

– Staged or phased: move batches over time

– Hybrid: run on-premises and cloud together during a longer transition

– IMAP or third-party tools: for non-Exchange sources

What else needs to move

– Calendars, contacts, and shared mailboxes

– Distribution lists and groups

– Files from file servers or other storage (to SharePoint and OneDrive)

– Teams and chat data, where possible

– Devices, enrollment, and policies

– Licensing and user accounts

Planning steps

1. Inventory mailboxes, sizes, aliases, groups, and special cases

2. Clean up old data and unused accounts

3. Prepare DNS and identity, including a plan for the MX record switch

4. Pilot with a few users

5. Communicate the schedule and what users need to do

6. Migrate in batches, with monitoring

7. Cut over mail flow

8. Reconfigure devices and Outlook profiles

9. Support users closely the first week

10. Decommission the old system only after a safe waiting period and a backup

Tenant-to-tenant challenges

– Domain can only be in one tenant at a time, so sequencing matters

– Preserving permissions and sharing links

– Teams and SharePoint structure

– Coexistence of calendars and free/busy information during transition

Tip

Set up Microsoft 365 security (MFA, Conditional Access, backup) as part of the migration, not months later.

DBR Soft handles Microsoft 365 migrations of all sizes. Contact us for more information.