Microsoft Teams Migration: Planning, Process, and Best Practices

Pre-Migration Planning to Migrate Teams from One Tenant to Another

 Every IT team should perform a detailed preliminary assessment before starting the migration. This assessment should cover Teams, permissions, dependencies, licensing, security, and data volumes. It helps identify potential risks, define migration priorities, and establish a clear roadmap for a controlled and successful migration. Here are the key pre-migration steps to complete before starting the migration:

1. Export the app catalog and record app status: Go to Teams admin center → Manage apps and export the full app catalog as CSV, including each app’s Allowed/Blocked status. Allowed means available to everyone; Blocked means available to no one. Use this status to filter users in later steps.
2. Review permission policies and allowed/blocked apps: Go to Manage apps → Permission policies, open each policy, and record allowed/blocked apps. Alternatively, run:

Get-CsTeamsAppPermissionPolicy

To view all default apps:

$msftApps = Get-CsTeamsAppPermissionPolicy -Identity “Global” | Select-Object -ExpandProperty DefaultCatalogApps $msftApps.id

Collect apps permitted in each policy and merge this information with the Manage Apps export. Apps blocked in Manage Apps remain blocked regardless of policy assignments.

3. Identify users assigned to each policy: Teams admin center: Go to Users → Manage users → Filter, select the required policy, click Apply, and export the filtered users to CSV. PowerShell: For each custom policy, use Get-CsOnlineUser with TeamsAppPermissionPolicy, excluding soft-deleted users; export Identity, DisplayName, UserPrincipalName, TeamsAppPermissionPolicy, AccountEnabled, AccountType to users_<policy>.csv. Skip Global and remove the TAG: prefix when present. Report policies with no user assignments. 

Finally, combine app catalog status + policy app permissions + user assignments to determine effective app access per user. 

See Microsoft’s documentation for detailed user interface instructions, screenshots, complete PowerShell scripts, and examples.

Microsoft 365 Migration Orchestrator for Teams to Teams Migration

Microsoft 365 Migration Orchestrator functions by moving user-level data (Exchange mailboxes, OneDrive personal files, and Teams chats) in coordinated, cross-tenant batches using Graph APIs or PowerShell. Because the Microsoft Tool “moves content, not identities,” the target environment must be entirely pre-staged before any data flows. Alternatively, you can use the Office 365 Tenant-to-Tenant Migration for a complete data migration with 100% accuracy.

Phase 1: Purchase & Licensing Setup

Before technical execution, required licenses must be active in both tenants:

• Target: Active, unassigned licenses including Exchange Online and Teams (for example, M365 E3/E5).
• Migration: A Cross-Tenant User Data Migration add-on license is mandatory and must be assigned once per user to either the source or target user object.

Phase 2: Teams Migration Tenant to Tenant Configuration & App Consent

Migration orchestration must be performed by a Global Administrator or Microsoft 365 Migration Administrator in the target tenant.

1. Establish cross-tenant trust using organization relationship domain names.
2. Register/authorize required applications and grant application-level Graph permissions using:
   • Grant-CTMSAppPermissions – Cross-Tenant Migration Service
   • Grant-OneDriveAppPermissions – OneDrive
   • Grant-CTTMAppPermissions – Teams Chat
   • Grant-MMSAppPermissions – Teams Meetings; run in both source and target.

Phase 3: Identity Pre-Creation & Mapping

Target users must exist but must not yet have active mailboxes or OneDrive sites.

1. Connect with Connect-ExchangeOnline and create target users as MailUsers using New-MailUser.
2. Create a Mail-Enabled Security Group in the source to strictly scope users permitted to migrate teams from one tenant to another.
3. Map exact source UPNs to target UPNs through the Microsoft Identity Mapping service.

Phase 4: Migration Batches

The native workflow supports a maximum of 100 users per batch.

1. Connect to Microsoft Graph from the target environment.
2. Create a CSV containing target user email addresses under EmailAddress.
3. In EAC → Migration → Add migration batch, select Cross-tenant migration, choose the configured endpoint, import the CSV, and submit.
4. Monitor processing; the Orchestrator manages dependencies, including Exchange and Teams workloads.

Phase 5: Validation & Cleanup

1. Source mailboxes are converted to MailUsers with target forwarding information.
2. OneDrive migration provides redirects so original sharing links can continue working.
3. After all batches finish, run Remove-SPOCrossTenantRelationship in both tenants to sever the relationship before source licenses expire.

Follow Microsoft 365 Migration Orchestrator for detailed commands, prerequisites, configuration, batch execution, monitoring, troubleshooting, and steps not covered above.

Limitations of the Microsoft 365 Migration Orchestrator

• No Collaborative Spaces: The native orchestrator ignores shared spaces like Teams, Channels, and SharePoint site collections, migrating only user-scoped data.
• No Delta Sync Automation: Cross-tenant OneDrive moves are a one-time migration activity; incremental or delta passes cannot be performed.
• Compliance Hold Blockers: Mailboxes or folders under litigation, eDiscovery, or Purview compliance retention holds are blocked from migrating by the native framework.
• Chat Formatting & Thread Changes: Participant configurations may change, interactive assets such as Loop components may be dropped, and duplicate threads may occasionally be generated.
• Sizing & Throttling Limits: The native pipeline enforces strict data-queuing caps, with roughly 100 concurrent users for active Teams chat and meeting processing to manage API throttling.

SysInfo Microsoft Teams Migration Tool

SysInfo Microsoft 365 Tenant Migration Tool is secure Windows software that migrates Teams between tenants using OAuth 2.0 and the Teams Migration API. This requires administrator access, support for HTTPS transport with TLS encryption, incremental migration, date range filtering, duplicate detection, and advanced encryption for integrity, security, compliance, and performance. In addition, this tool performs Microsoft 365 Tenant-to-Tenant Migration with complete data, including OneDrive files, SharePoint sites (drives and lists), calendars, and contacts.

Microsoft Teams Migration Steps:

1. Install & Launch: Download and launch SysInfo Tenant to Tenant Migration Software with administrator privileges. Select the Teams migration option. Additionally, you can also Copy Mailboxes, SharePoint, and OneDrive.
2. Add Source Connection: Add and authenticate the source Microsoft 365 tenant using the required administrator/OAuth credentials, then establish the source connection.
3. Map Mailboxes: After authentication, select the target/destination accounts and map source-to-destination accounts manually or automatically. Apply available filters for precise migration and proceed.
4. Migrate & Verify: Click Start Migration to begin. Monitor live processing through the Active Tasks migration dashboard. Use All Reports to view the real-time migration status of Microsoft 365 components and verify migration results.

Teams Migration Best Practices

• Plan & assess: Start by deciding what needs to be migrated, when it should happen, who will be involved, and what a successful migration should look like. Review users, Teams, channels, permissions, dependencies, data volumes, and any compliance holds.
• Prepare both tenants: Make sure both tenants have the required licenses, domains, permissions, endpoints, and application consent. Ensure the users who will be migrated are properly prepared and mapped.
• Clean up: Remove old or unnecessary Teams and data. Check team owners, members, apps, permissions, security, retention, and compliance requirements before migration.
• Pilot first: Begin with a small group of representative users and test Teams, channels, files, meetings, permissions, and the overall user experience before moving everyone.
• Execute in controlled batches: Migrate users in manageable batches while considering workload dependencies. Check the migration progress, errors, performance, and readiness.
• Manage coexistence: If the migration happens in phases, plan mail routing, calendar free/busy, and Teams federation so users can continue working with minimal disruption.
• Validate & reconcile: After migration, check users, Teams, channels, memberships, permissions, files, and important business functions. Record any failures and resolve them.
• Post-migration: Complete the cutover, remove temporary migration settings, monitor Teams usage, support and train users, gather feedback, and maintain proper naming, lifecycle, retention, security, access, and governance policies.

Conclusion

A successful Microsoft Teams migration is ultimately about protecting business continuity, keeping people connected to user access, and collaboration, not simply moving data. You know, attentive planning, accurate assessment, the right migration approach, controlled execution, and detailed validation reduce risks and downtime by a huge amount. Using Microsoft’s native capabilities or a professional migration tool, supported by strong governance, organizations can confidently transition users and data while maintaining security and productivity. Now it’s time to start the actual migration.

Frequently Asked Questions

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