Migrate Exchange Online Mailbox to Exchange Online: Best Practices for IT Admins

What Does Exchange Online to Exchange Online Mailbox Migration Mean?

Exchange Online to Exchange Online migration simply means moving mailboxes between two different Microsoft 365 tenants. For example: Source Tenant (companyabc.onmicrosoft.com, john@companyabc.com) -> Destination Tenant (companyxyz.onmicrosoft.com, john@companyxyz.com). After migration, users can access their emails, folders, contacts, and calendars from the new tenant instead of the old one.

Reasons for Migrating from Exchange Online to Exchange Online

• Company Merger: When two companies merge, employees need to work under a single Microsoft 365 tenant. Migrating Exchange Online mailboxes helps centralize communication and simplifies IT management. Example: Company A acquires Company B. Instead of managing two Microsoft 365 environments, the IT team migrates all Exchange Online mailboxes into one tenant.
• Business Acquisition: After another organization, businesses migrate employee mailboxes into their existing Microsoft 365 environment. This ensures: One email system, Easier user management, Better compliance, and Simplified licensing.
• Tenant Consolidation: Large organizations sometimes manage multiple Microsoft 365 tenants across different departments or countries. Maintaining several tenants increases administrative work, licensing complexity, security management, and user management.

Mailbox Migration: Supported Data, Common Challenges, & Pre-Migration Checklist

• What Data Can Be Migrated? A complete Exchange Online migration typically includes: Emails, Attachments, Inbox Folder Structure, Contacts, Calendars, Tasks, Notes, Shared Mailboxes, and Archive Mailboxes.
• Challenges During Exchange Online Mailbox Migration: Large Mailbox Sizes, Downtime, Permission Mapping, Data Integrity, User Mapping, and Authentication Requirements.
• Pre-Migration Checklist: Verify Microsoft 365 admin access, create destination user mailboxes, assign appropriate licenses, check mailbox size, enable Modern Authentication, verify Internet Connectivity, inform End Users, and back up important data.

Is Manual Exchange Online Mailbox Migration Possible?

Yes. Microsoft provides a manual method for cross-tenant mailbox migration. However, these methods require appropriate permissions, tenant configuration, and technical expertise. They may also involve additional setup and can become complex for large-scale migrations.

Steps to Manually Migrate Exchange Online Mailbox to Exchange Online

1. Firstly, sign in to both the source and destination Microsoft 365 tenants with Global Administrator or Exchange Administrator permissions.
2. Now, create user mailboxes in the destination tenant and assign the required Exchange Online licenses.
3. Configure the cross-tenant organization relationship between both tenants.
4. Then, create migration endpoints in the Exchange Admin Center.
5. Map the source mailboxes to the destination mailboxes.
6. Create a migration batch and start the mailbox migration.
7. Monitor the migration progress and fix any errors if they occur.
8. Once the migration is complete, verify the mailbox data and update DNS records if required.

Professionally Migrate Exchange Online Mailbox to Exchange Online

From small to large enterprise users, the DRS Softech Cross Tenant Migration Tool is the best choice. It allows users to perform mailbox migration without any data loss. Secure authentication options: Modern Authentication and Admin Impersonation. Option to review all important mailbox details, like license type, estimated mailbox size, and mailbox category (User and Shared). Two destination options: convert to PST and tenant-to-tenant migration. Different Mapping, features (Remove Duplicates, Skip Previously Migrated Data, and more).

Steps to Move Mailbox from Exchange Online to Exchange Online

1. Download the DRS Softech Microsoft 365 Cross Tenant Migration. Click Copy and Mailbox Migration.
2. Authenticate the source Microsoft 365 tenants using Modern Authentication or Admin Impersonation (Azure App Registration).
   
3. Review User ID, License Type, and Mailbox Size. Select the mailbox user ID to migrate. Continue to Select Destination.
   
4. Authenticate the destination Office 365 tenants using Modern Authentication or Admin Impersonation.
5. Map from source to destination; select what you migrate (Contacts, Calendars, Emails).
6. Apply advanced features and filters as needed. Press Start Migration.

Major Benefits of Using DRS Softech O365 Tenant to Tenant Migration Tool

• Migrate multiple Exchange Online mailboxes at once with accurate results.
• Perform SharePoint Migration, OneDrive Migration, Email Deduplication, SharePoint Deduplication, and OneDrive Deduplication.
• Simple Interface, which means every user can easily use it. A live monitoring report is available.
• Compatible with all Windows versions, including Windows 11, 10, and more.
• Trial version saves 500 Emails per Folder, 100 Contacts & 100 Calendar Items per User.

Conclusion

This guide explains all the necessary information to migrate Exchange Online Mailbox to Exchange Online. Microsoft offers a manual method for this cross-tenant mailbox migration. But it has several limitations. Therefore, it’s best to use the professional tool. It migrates multiple Exchange Online mailboxes at once without any downtime. Multiple features you can use with this tool. Also, try the demo version and one-time service of this tool. 

Frequently Asked Questions