Microsoft 365 Tenant-to-Tenant Migration

Client Overview for Microsoft 365 Tenant-to-Tenant Migration

A multinational organization undergoing a corporate restructuring needed to migrate its Microsoft 365
environment from one tenant to another. The project involved migrating users, mailboxes, and OneDrive data,
Microsoft Teams, SharePoint sites, and associated permissions while ensuring minimal disruption to
business operations.

Industry

Professional Services

Users Migrated

500+ Users

Project Scope

• Exchange Online Mailboxes
• OneDrive for Business
• SharePoint Online
• Microsoft Teams
• Distribution Groups
• Shared Mailboxes
• User Accounts and Licenses
• Domain Migration

Business Challenge

The client had recently undergone a business acquisition and needed to separate its Microsoft 365
environment from the parent company.

Key challenges included:

• Migrating over 15 TB of business-critical data
• Preserving user access and permissions
• Maintaining email continuity
• Avoiding business disruption during working hours
• Ensuring secure data transfer and compliance
• Managing migration across multiple departments and locations

The client required a seamless migration with minimal downtime and a clear rollback strategy.

Mignet’s Solution

Mignet designed and executed a structured migration approach consisting of the following phases:

1. Assessment & Discovery

Our team conducted a comprehensive analysis of:

• Existing Microsoft 365 tenant configuration
• User accounts and mailbox sizes
• SharePoint sites and permissions
• Teams structure and channels
• OneDrive storage usage
• Domain dependencies

A detailed migration roadmap was prepared based on the findings.

2. Migration Planning

The project plan included:

• Migration waves based on departments
• Communication plan for end users
• Risk assessment and mitigation strategy
• Cutover schedule
• Validation and testing procedures

3. Tenant Preparation

The destination tenant was configured with:

• User accounts
• Security policies
• Licensing assignments
• Conditional access policies
• Exchange Online settings
• SharePoint and Teams configurations

4. Data Migration

Using enterprise-grade migration tools, Mignet successfully migrated:

Exchange Online

• User mailboxes
• Shared mailboxes
• Calendar data
• Contacts
• Distribution groups

OneDrive for Business

• Personal files and folders
• Sharing permissions
• User ownership

SharePoint Online

• Team sites
• Document libraries
• Permissions and access controls

Microsoft Teams

• Teams structure
• Channels
• Memberships
• Files and documents

5. Domain Cutover

The organization’s primary email domain was migrated to the new tenant during a scheduled maintenance
window.

Activities included:

• DNS updates
• Mail flow validation
• Autodiscover configuration
• User profile verification

6. Post-Migration Support

Following the migration, Mignet provided:

• End-user support
• Mail flow monitoring
• Performance validation
• Security checks
• Knowledge transfer sessions

Results

Key Outcomes

500+ Users Successfully Migrated
15 TB+ Data Migrated Securely
Less Than 2 Hours of User Impact
Zero Data Loss
100% Mailbox Integrity Maintained
Seamless Email Continuity
Improved Security and Compliance Controls

Client Benefits

The new Microsoft 365 tenant provided:

• Enhanced administrative control
• Improved security governance
• Better compliance management
• Simplified user management
• Optimized licensing costs
• Increased operational independence

The migration was completed on schedule and within budget while maintaining business continuity
throughout the project.

Why Mignet?

Mignet specializes in Microsoft 365 migration and managed services, helping organizations execute
complex cloud transformation projects with confidence.
Our expertise includes:

• Tenant-to-Tenant Migrations
• Microsoft 365 Deployments
• Exchange Online Migrations
• SharePoint & Teams Migrations
• Azure AD Services
• Security & Compliance Solutions
• Managed IT Services

Need to migrate your Microsoft 365 environment?

Contact Mignet to discuss your migration requirements and discover how we can ensure a secure,
seamless transition.