Controlling settings, permissions, and membership within Teams and channels
Hello Joanne Pollitt-Wright,
Thank you for explaining your organization’s situation.
If the old and new accounts belong to two different Microsoft 365 tenants, this would be considered a cross-tenant migration rather than a simple merge of two Teams.
If your primary requirement is to move the stored files and SharePoint content, your IT administrators can review the following options:
1/ Cross-tenant SharePoint migration: Can move supported SharePoint sites between tenants, including Microsoft 365 group-connected sites associated with Teams, modern sites, classic SharePoint sites, and communication sites. However, this option is currently available only to eligible Enterprise Agreement customers and requires the applicable cross-tenant migration licenses.
Please also note that migrating a Teams-connected SharePoint site moves only the SharePoint site content. It does not migrate the Teams content, channels, conversations, or the associated Teams structure.
You can review the requirements and supported content here: Cross-tenant SharePoint site migration overview | Microsoft Learn
2/ FastTrack cross-tenant migration service: FastTrack provides guidance and migration services for supported workloads such as Exchange Online, SharePoint, and OneDrive.
Further information is available here: Cross-Tenant Migration: FastTrack for Microsoft 365
Since your environment contains years of class, assignment, Team, and shared-drive content, I strongly recommend that the IT administrators for both organizations work with a Microsoft technical support engineer or an experienced Microsoft 365 migration specialist before making changes. The engineer can help assess which workloads can be migrated through Microsoft tools and which Teams components require a separate migration approach.
To open a ticket support: Get support - Microsoft 365 admin | Microsoft Learn
Kind regards,
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