The Ultimate Checklist For A Successful
Microsoft 365 To 365 Migration


Transitioning from one Microsoft 365 tenant to another can be intricate and lengthy, particularly in the absence of thorough preparation. Whether you’re navigating a business merger, an acquisition, or a restructuring of your organization, migrating between Microsoft 365 tenants necessitates meticulous planning to maintain data integrity, reduce downtime, and provide a smooth experience for users.

This detailed checklist will assist you throughout the entire journey—from initial preparation to the post-migration phase—ensuring that your tenant-to-tenant Microsoft 365 migration is executed successfully.


Pre-Migration Planning


Understand the Business Requirements

Start by determining the motivations behind the migration. Is it prompted by a merger, acquisition, or a rebranding effort? Understanding these objectives is essential for establishing priorities and setting timelines.


Define the Scope of the Migration

Determine the items that require migration:

  • Email accounts (including emails, calendars, and contacts)

  • Files stored in OneDrive for Business

  • SharePoint Online sites

  • Data from Teams

  • Microsoft 365 Groups

Perform a Full Audit

Utilize Microsoft applications such as the Microsoft 365 Admin Center and PowerShell scripts to conduct an audit of the following:

  • The total count of mailboxes

  • The volume of mailbox data

  • Licenses currently active and services being utilized

  • Shared mailboxes along with their respective permissions

  • Custom domains and associated DNS records


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Choose the Right Migration Method

There are multiple approaches to migrating from Microsoft 365 to Microsoft 365:

  • Manual migration

  • Utilizing third-party solutions like BitTitan, Quest On Demand Migration, or Cloudiway

  • Employing Microsoft’s built-in PowerShell scripts (which have certain limitations)

The best method for your migration will depend on factors such as the complexity of your data, the skills of your team, and your project timeline.


Prepare the Source and Target Tenants


Now that a strategy has been established, it's essential to set up both environments to guarantee they work well together and minimize mistakes during the migration.


Verify Domain Ownership

Domains slated for transfer need to be deleted from the original tenant and confirmed in the new one. Please note that transferring a domain necessitates adjustments to DNS settings, which could lead to brief service interruptions.


License Assignment

Verify that the intended tenant possesses a sufficient number of licenses for all users. Align the types of licenses to maintain uninterrupted service (such as Exchange, SharePoint, and Teams).


Enable User Accounts and Services

Set up user accounts in the destination tenant in advance and designate the necessary roles and services. This approach is particularly beneficial when preparing for a cut-over migration.


Communicate With End Users

Keep users informed by providing consistent updates regarding the following:

  • Schedule for the migration process

  • Actions that users may need to take

  • Possible periods of service interruption

  • Contact details for IT support or helpdesk assistance

Migration Execution


The essential stage encompasses the transfer of data itself. It is vital to ensure accurate timing, precision, and continuous oversight to prevent any loss of data or interruptions in service.


Mailbox Migration

Utilize PowerShell scripts or an external tool to transfer mailboxes. For larger mailboxes, think about implementing a staged migration to minimize extended periods of inactivity.



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Migrate OneDrive and SharePoint

Utilize either Microsoft's SharePoint Migration Tool (SPMT) or an alternative third-party application. It's important to accurately map user permissions and shared links to prevent any confusion after the migration process.


Teams and Groups Migration

The process of transferring Microsoft Teams is intricate due to several factors, including:

  • Conversation history

  • Files within channels

  • Applications and integrations

  • Private channels

Perform Validation Checks

Once the data has been transferred, carry out quality assurance checks:

  • Conduct random inspections of migrated mail accounts

  • Ensure folder hierarchies and access rights are correct

  • Validate that SharePoint document libraries remain unaffected

  • Assess the functionality and accessibility of Teams

Post-Migration Steps


After migration is finished, it is crucial to follow up with post-migration actions to guarantee user contentment and maintain ongoing stability.


Update DNS and Domain Settings

Direct the MX, CNAME, and any other essential records to the new tenant. Verify that email delivery is restored promptly without any interruptions.


Monitor and Troubleshoot

Be alert for any problems with logging in, absent files, or delays in email delivery. Utilize the Microsoft 365 Admin Center along with user feedback to identify and address these concerns.


Train and Support Users

Offer educational resources or real-time assistance to aid users in adjusting to the updated environment. Pay particular attention to alterations in file locations, Teams organization, or shared access permissions. To uncover more, simply click the link.