Migrate to Microsoft 365
Microsoft 365 Tenant-to-Tenant Cutover Email Migration
IT Partner provides planning, design, and migration of email service from one Microsoft 365 tenant to another.
$35 per mailbox + $3,500 tenant fee5 weeks
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Microsoft 365 Group Mailbox Tenant-to-Tenant Migration
Microsoft 365 Group with Mailbox Tenant-to-Tenant Migration moves Microsoft 365 Groups and their group mailboxes — conversations, calendar, and mailbox settings — from one Microsoft 365 tenant to another during mergers, acquisitions, and tenant consolidations. The honest boundary matters here: Microsoft's native cross-tenant migration tooling does not cover Microsoft 365 Group mailboxes, and group-connected SharePoint content and Teams channels always migrate under their own scopes. IT Partner recreates the groups in the target tenant, migrates the group mailbox data, and validates the result, at $35 per group mailbox over 5 days, as part of a tenant-to-tenant mailbox migration project.
01 — Overview
What this engagement is
Microsoft 365 Groups provide shared collaboration resources — a collective inbox, shared calendar, and a connected SharePoint document library — with permissions assigned automatically as members are added. This service covers the mailbox side of that picture in a tenant-to-tenant move: the groups are recreated in the target tenant with their names, memberships, and permissions, and the group mailbox content (conversations and calendar) is migrated across. Buyers should know the platform reality: Microsoft 365 Group mailboxes are not covered by Microsoft's native cross-tenant migration orchestration, so group mailbox moves rely on migration tooling scoped to mailbox data, and the group-connected SharePoint site, files, Planner plans, and any Teams channels attached to a group migrate under separate scopes — IT Partner's SharePoint Online and Teams tenant-to-tenant migration services cover them. This service runs as part of a broader IT Partner tenant-to-tenant mailbox migration project, which supplies the user identity mapping and mail-flow cutover the group migration depends on.
02 — Outcomes
Success criteria
01In-scope Microsoft 365 Groups are recreated in the target tenant with the agreed names, memberships, and permissions.
02Group mailbox data — conversations, calendar items, and mailbox configuration within the migration tooling's capabilities — is migrated from the source tenant to the target tenant and verified.
03The migration process causes as little disruption as possible, with mail-flow cutover coordinated through the broader tenant-to-tenant migration plan.
03 — Deliverables
What you receive
✓Migration planning and preparation by assessing the environment and setting up the target tenant.
✓Configuration of the source and target environments for migration, including setting up the necessary permissions and creating a migration batch.
✓Detailed inventory of all the Microsoft 365 groups, including their names, sizes, permissions, and any specific configurations.
✓Monitoring of the migration progress.
✓Verification that all data has been successfully migrated and completion of any necessary post-migration tasks.
✓Migration process designed to minimize user intervention.
✓Creation of Microsoft 365 Groups.
✓Groups mailboxes migration start.
✓Changing MX record to new Microsoft 365 tenant.
✓Final group migration.
04 — Plan
How the work unfolds
Kickoff meeting.
Confirm the group migration scope, source and destination tenant details, group inventory expectations, contacts, schedule, and dependencies on the broader tenant-to-tenant mailbox migration project.
Pre-migration source system health check.
Review source tenant readiness and build the detailed inventory of in-scope Microsoft 365 Groups — names, sizes, memberships, permissions, and specific configurations — and flag groups with connected content (SharePoint, Teams, Planner) that requires separate scope.
Creating Microsoft 365 Groups.
Create the in-scope groups in the target tenant with the agreed naming, membership, and permission configuration, mapped to migrated user identities.
Groups Mailboxes migration start.
Configure the migration tooling and begin synchronizing group mailbox conversations and calendar data to the target tenant, monitoring for errors and throughput issues.
Verification of groups migration.
Validate migrated group mailbox content and configuration against the inventory, including representative conversations, calendar items, and membership-driven access.
Changing MX record to new Microsoft 365 tenant.
Coordinate the mail-flow cutover with the broader tenant-to-tenant migration schedule so mail addressed to group addresses is delivered to the new tenant.
Final group migration.
Complete the final synchronization pass after cutover, confirming remaining delta items are transferred.
Post-migration tasks.
Complete final validation, review results and exceptions with the client, and confirm group access from supported clients before closure.
05 — Before we start
Prerequisites
→Tenant to tenant mailbox migration project from IT Partner.
06 — Working together
Who does what
IT Partner
- Plan and prepare for the migration by assessing the environment and setting up the target tenant.
- Configure the source and target environments for migration, including setting up the necessary permissions and creating a migration batch.
- Detailed Inventory. Create a detailed inventory of all the Microsoft 365 groups that includes their names, sizes, permissions, and any specific configurations.
- Monitor the progress of the migration.
- Verify that all data has been successfully migrated and perform any necessary post-migration tasks.
- Minimize user intervention during the migration process.
Your team
- Provide a dedicated point of contact responsible for working with IT Partner.
- Coordinate any outside vendor resources and schedules.
07 — Scope
What's not included
✕Group-connected SharePoint sites and document libraries — these migrate under the separate SharePoint Online Tenant-to-Tenant Migration service.
✕Teams channels, tabs, apps, and channel conversations attached to team-connected groups — covered by the separate Microsoft Teams Tenant-to-Tenant Migration service.
✕Planner plans, Power BI workspaces, Viva Engage communities, and other group-connected workloads unless separately scoped.
✕User mailboxes, shared mailboxes, and archive mailboxes — these migrate under the broader tenant-to-tenant mailbox migration project and its sibling services.
✕End-user device reconfiguration, Outlook profile rebuilds, and desktop support.
✕Remediation of pre-existing tenant, identity, or compliance issues beyond what the group migration requires.
08 — Fine print
Limitations & technical notes
!Microsoft 365 Group mailboxes are not covered by Microsoft's native cross-tenant migration orchestration; group mailbox moves rely on migration tooling scoped to mailbox data, with capabilities confirmed during planning.
!Group-connected content (SharePoint files, Teams channels, Planner) does not move with the group mailbox and requires its own migration scope.
!Migration timing and throughput depend on Microsoft 365 service health, tenant throttling, group mailbox sizes, and source tenant condition.
!Group membership and permissions in the target tenant depend on the user identities having been migrated or mapped by the broader tenant-to-tenant migration project.
!Mail-flow cutover for group addresses follows the domain and MX sequencing of the broader migration plan.
09 — Questions
Frequently asked questions
What does the Microsoft 365 Group with Mailbox Tenant-to-Tenant Migration service do?
It recreates Microsoft 365 Groups in a new tenant and migrates their group mailbox data — conversations and calendar — during mergers, acquisitions, and tenant consolidations, with verification against a detailed inventory. It runs as part of an IT Partner tenant-to-tenant mailbox migration project.
Does this migrate the full group workspace, including the document library and Teams channels?
No — and that boundary is deliberate. The group-connected SharePoint site and files migrate under the SharePoint Online Tenant-to-Tenant Migration service, and Teams channels under the Teams Tenant-to-Tenant Migration service. This service covers the group objects and their mailbox content; IT Partner flags any group with connected content during inventory so nothing is silently dropped.
Is there a native Microsoft tool that moves Microsoft 365 Groups between tenants?
No. Microsoft's native cross-tenant migration covers user mailboxes, OneDrive, and (in preview) Teams chats — Microsoft 365 Group mailboxes are not included. Group moves therefore combine group recreation in the target tenant with mailbox-scoped migration tooling, which is exactly how this service is built.
What data is migrated for each group?
Group mailbox conversations, calendar items, and mailbox configuration within the migration tooling's capabilities, plus the group itself — name, membership, and permissions — recreated in the target tenant and validated against the pre-migration inventory.
How much does the service cost, and how long does it take?
The service is $35 per group mailbox over a 5-day engagement, quoted in writing before work begins. Scheduling is coordinated with the broader tenant-to-tenant mailbox migration project.
What are the prerequisites for this service?
A tenant-to-tenant mailbox migration project from IT Partner — it supplies the identity mapping and mail-flow cutover this migration depends on — plus a dedicated client point of contact and coordination of any outside vendor resources and schedules.
What information does IT Partner collect before migrating the groups?
A detailed inventory of the in-scope Microsoft 365 Groups: names, sizes, memberships, permissions, and specific configurations, with connected content (SharePoint, Teams, Planner) flagged for separate scoping. The inventory drives both the migration and the post-migration verification.
How is mail flow to group addresses handled during cutover?
The MX record change to the new tenant is coordinated through the broader tenant-to-tenant migration plan, so mail addressed to group addresses delivers to the new tenant after cutover, with a final synchronization pass catching remaining delta items.
Will users need to do anything during the migration?
The migration is designed to minimize user intervention: IT Partner handles planning, configuration, migration, monitoring, and verification. Group members simply use the recreated groups in the new tenant once their own accounts are cut over.
How does IT Partner verify the migration completed successfully?
Migrated group mailbox content and configuration are validated against the inventory — representative conversations, calendar items, membership, and permissions — and results and any exceptions are reviewed with your point of contact before closure.
Is downtime expected during the group mailbox migration?
Group mailbox data synchronizes while the source stays in service, and cutover timing follows the broader migration schedule. The service aims for as little disruption as possible but does not promise a zero-impact cutover; expected impact is confirmed during kickoff.
What is not included in this service?
Group-connected SharePoint sites and libraries, Teams channels and apps, Planner and other connected workloads, user and shared mailboxes, archive mailboxes, device and Outlook profile reconfiguration, and remediation of pre-existing tenant issues. Each is covered by its own IT Partner service or scoped separately.
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$35 per mailbox + $500 tenant fee
5 days