Office 365 Group to Office 365 Group Mailbox Migration

Read time: 8 minutes

Microsoft 365 Groups are collaborative workspace for users that allow them to access all the common resources shared by the team. Here, users can hold meetings, share documents, send & receive emails, and track project progress. Typically, users migrate their Office 365 Group data during mergers or to convert existing personal mailboxes to shared workplaces.

In this article, we will talk about the basics of an Office 365 Group, why Office 365 Group migration is necessary, the native options for migration, and the full guide to migrate Office 365 Groups data.

What are Office 365 Groups?

Office Groups is an advanced service offered by Microsoft that works with any Office 365 plan, which you are already using with your subscription. With Office 365 Groups, you can easily collaborate and communicate with your teammates sharing documents, spreadsheets, or working on any other project. Once a Group is created, a new Outlook Shared mailbox, a SharePoint library, a calendar, and a OneNote notebook is created along with it. You can select specific people that you want to communicate with and add them to Groups, and then set up a collection of resources for those people to share. Main components of an Office 365 Group include:

Shared email conversations: All the emails sent to the group’s email address are stored in a shared mailbox. This way, all the members of the group can easily access and reply to the discussions going on in the Group.
Shared mailbox: Mailbox of an Office 365 Group acts as a central channel of communication for all the group members. The members can easily send and receive emails using the Group’s shared email addresses.
Shared calendars: Group members get a common calendar that can be used to schedule meetings, events, and important deadlines. This makes coordinating with the entire team a lot easier.
SharePoint library: All the documents shared in the Group are stored in this SharePoint library so that the members can easily view and edit all the files.

When is it Necessary to Migrate Office Groups to Another Groups?

Many organizations perform Office 365 Group to Office 365 migration during changes in the work environment and to maintain business continuity. Here are some of the most common migration scenarios:

Company mergers or acquisition: During mergers or acquisition, organizations often merge their Microsoft 365 environments into one single tenant. This helps to preserve important resources during mergers, without affecting the workflow.
Office 365 tenant to tenant migration: Admins perform Office 365 Group mailbox migration to shift Groups data from one tenant to another. It’s a common thing to do during consolidation of cloud platforms or while shifting from On-Prem to a cloud platform.
Domain merger: Some companies combine multiple email domains into one single domain to save up space and maintain consistent collaboration across the whole tenant. In this situation, admins also migrate Office 365 Groups too so that no data is left behind.
Company Restructure: When an organization is restructured, new teams and departments are created. This also calls for Office 365 Group migration so that employees still have the access to important conversations, shared documents, and important dates and deadlines in the calendars.
Splitting of Microsoft 365 tenant: Companies regularly divide a particularly large tenant into two or more tenants because of either compliance requirements or due to business divestiture.

Does Microsoft Provide Native Options to Migrate Office 365 Group Data?

Microsoft does provide some native options to migrate Office 365 Groups data individually, but there isn’t any all-in-one option present to migrate all data of the Groups. Office 365 Groups data isn’t just the mailbox files, it also includes data from Microsoft Teams, SharePoint Online, Exchange Online, and others. Admins often have to run multiple migration jobs to shift all the data separately.

After migration, Admins have to recreate Group components like:

Conversations in the Group mailbox.
Existing memberships and ownerships settings.
Existing permissions for SharePoint and Microsoft Teams.
Calendar deadlines and meetings.

Pre-migration Checklist for Office 365 Group Mailbox Migration

Before proceeding with full-fledged migration, it’s necessary for users to check and verify some important things to perform a smooth and error-free migration.

Backup all the essential data: Before doing anything, backup and create multiple copies of your data as per the 3-2-1 backup rule. Having a backup is necessary to protect your data in case of cyberattacks and even helps in instant recovery.
Relevant permissions: Make sure that you have the required permissions to shift all the Office 365 Groups data. Roles like Global Administrator or User Administrator with relevant permissions are needed to perform functions like creating Groups, managing users, and configuring settings for migration.
Full access of the source Group: Check that you have full access and all the necessary permissions to migrate the Office 365 Groups. Make sure that the Group’s mailbox, SharePoint site, calendar, and all the other Microsoft 365 services can be easily accessed.
Check that you have all licenses: Before proceeding with the migration, verify that all the users have the necessary Microsoft 365 licenses according to their role and privilege. Also, make sure that users have specific licenses required for certain Microsoft 365 services like SharePoint Online, Exchange Online, Microsoft Teams, etc.
Clean up the source Office 365 Groups: Review the source Office 365 Group and remove all the obsolete and unused Groups. This will help in shortening the migration time and reduce unnecessary data clutter in the destination Office 365 Group.
Inform users about migration: Inform all the details about migration to users like full schedule, any expected downtime, and if any of the services will get affected or not. This will help avoid confusion and prepares users in advance for the changes ahead.

How to Migrate Office 365 Groups Manually?

Microsoft doesn’t provide any direct manual method for Office 365 tenant to tenant migration. Instead, admins can take the help of multiple native Microsoft tools to migrate Office 365 Groups data. This approach is suitable for small scale migration of Groups with limited data. Two most common approaches to perform Office 365 Group mailbox migration are the Export method via Exchange Admin Center and with the help of PowerShell.

In the export method, while mailbox data can be easily migrated via the Exchange Admin Center, files from SharePoint are migrated to the new Group via native tools of Microsoft. On the other hand, admins use PowerShell to create Office 365 Groups, assign owners, manage memberships and permissions, etc. It doesn’t necessarily perform full migration, rather helps in individual tasks of migration.

Post Office 365 Groups Migration Validation Checklist

Migrating data to the new tenant isn’t the end of the process. Admins need to perform multiple checks once Office 365 Group mailbox migration is complete. A thorough post-migration validation helps to assess if any data is missing or if there any issues with configurations or permissions. Some of these checks include:

Verify Group members: Compare all the Group members between source and destination to verify that all users have been migrated. Communicate with users and make sure that all users can access the shared resources in the new Group.
Check for email conversations: Look for the migrated Office 365 Group email conversations, files, and attachments in the new Group to see if all the data got migrated successfully.
Check the Shared Calendar: Review the Group’s shared calendar to make sure that all the meetings, deadlines, upcoming events, and reminders are intact. Check with users to see if they can still view and edit all the entries or not.
Verify permissions and ownerships: Check across the Office 365 Group and other services to see if all the permissions are configured to the authorized users only. Also, make sure that ownership is assigned to authorized users only.
Test mail flow once: Check the email flow once by sending and receiving emails at the Group email address. Make sure that the emails you send and receive can be accessed and edited by other Group members.

Is There Another Way to Migrate Office 365 Groups Data?

Manual works best for small scale migration or for one-time migration jobs. But if you have to migrate multiple Office 365 Groups or large sized Office 365 Groups, experts suggest taking the help of a trusted Office 365 Migration tool to simplify the whole process and reduce downtime. Kernel Office 365 Migration tool is one such tool that can help you migrate Office 365 Groups from one tenant to another. Also, it is capable of migrating Exchange mailboxes for both on-premises and hosted Exchange.

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Conclusion

Office 365 Group to Office 365 Group mailbox migration is more than just moving mailbox data from one Group to another. This process involves extensive planning and constant verification and validation so that migration process runs smoothly, and no data is lost. With proper planning and by following the best practices, you can safely migrate all your data safely to another Office 365 Group.