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Mergers & Acquisitions: How to Plan Your Office 365 Tenant Migration Strategy

Jul 31, 2020 by Mike Weaver

Two clouds over skyscrapers, representing an Office 365 tenant migration.

For companies undergoing mergers, acquisitions, or divestitures (MAD), there’s a need to combine, relocate, or consolidate IT infrastructure. This often means performing an O365 tenant to tenant migration, whether to merge multiple tenants into one, or separate one tenant into two.

While all organizations involved may use Office 365, it can make for a messy marriage or bitter breakup without the right integration solutions, as moving data and users between Office 365 tenants can be hugely challenging.

Common M&A IT Integration Mistakes

Consolidating your IT system quickly and efficiently is crucial, as delays can negatively impact business operations. Employees can get frustrated. Customers can be lost.

Here are some of the major mistakes M&As commonly make when approaching any IT integration, including O365 tenant migrations:

  • Not starting soon enough
    IT integration planning should start before the acquisition is finalized. An evaluation should be conducted that’s part of the due diligence. Knowing what it will take may should be a consideration in finalizing deal points, with timescales set in the Transitional Service Agreement (TSA). When you have a plan in place, and the deal closes, you can get started right away.
  • Not setting realistic timelines
    Setting unrealistic deadlines for migration is demoralizing. It can also harm the reputation of a new owner if a business-critical function doesn’t get completed on time. Set realistic timelines.
  • Outdated documentation
    Not every organization will have a complete inventory of hardware, software, applications, and data.
  • Not communicating across all departments
    IT integration affects nearly every employee in every department. Clear communication is needed to ensure everyone knows what’s going to happen and when. This is especially important with existing IT staff, who may be more worried about keeping their jobs than migrating data.

We discuss the importance of communicating change in this video:

To avoid these common mistakes, outlined below are strategic steps organizations should consider for an efficient Office 365 tenant migration.

Planning & Discovery

Perhaps the key step in any integration is planning. In fact, planning and discovery may take longer than the actual migration. The more precise your planning is, the smoother the transition will be. The goal of your planning is to prepare the project scope, ensuring both companies are ready for the consolidation, and to find any potential stumbling blocks.

If you’re familiar with on-prem to cloud migrations, but new to Office 365 tenant migrations, you’ll be surprised by the new challenges.

Project Scope

Your discovery phase is intended to document everything and eliminate as many surprises as possible that could slow down the process. This includes understanding the business, legal, and compliance requirements for data handling.

You’ll employ different strategies for your tenant migration, depending on which scenario you’re working with. Here are the most common:

  • Merge two cloud-only organizations
  • Merge a cloud-only organization into a hybrid organization

Another type of tenant to tenant migration is for divestitures. This occurs most commonly when spinning off a business unit from one tenant to a new business in a separate tenant:

  • Divesting from a cloud-only organization
  • Divesting from a hybrid organization

One thing to pay particular attention to during the discovery phase is licensing. When planning a tenant migration, we use our Office 365 management software to analyze license usage to determine requirements for the new tenant.

It certainly pays to get your licensing under control, especially when ROI is in sharp focus post-M&A activity.

Preparation for Both Companies

You should create test accounts in both the source and target tenants. You’ll need to license these accounts to make sure you can access Office 365 services. It helps to add email, calendar, and contact items to accounts to test the migration.

Some clients even create test domains to test the ejection and move process.

Office 365 to Office 365 Migration

There are two methods when it comes to the actual tenant migration.

The first is known as the ‘Big Bang’ migration, which is usually performed for smaller projects. Most of the migration execution and cutover can happen during a weekend or overnight. It’s the preferred method for small data instances and the most efficient, and as the technology continues to progress, we’re consistently seeing larger migrations concluded in a single weekend.

Enterprise migrations will likely have large amounts of data and may require the management of both systems side-by-side for an extended period.

In both cases, your goal is to limit any disruption to employees, customers, and business operations as much as possible.


A communication plan is another critical part of any IT migration. Users need to be notified in advance. Notifications should explain what’s happening and the impact it will have. If there’s going to be any downtime, make sure there’s ample notice so employees can prepare.

Include information on how to connect to Outlook on the internet updated sign-in information in case they experience any problems after the migration begins. Test migrations will help you know what to expect for changes to Outlook profiles and any reconfiguration to help prepare employees.

Analysis & Validation

Tenant to tenant migrations copy data from the source tenant. That means the original data is still accessible to check and ensure everything has been migrated.

Analysis It is important to note that cutting off access in the source is important to avoid users working in the wrong tenant and validation will confirm data has been transferred and everything’s working.

What to Expect with Quadrotech’s Office 365 Tenant to Tenant Migration Solution

Tenant to tenant migrations can be complex. You must have the correct tools to make the move as quickly and efficiently as possible to get business up and running.

Our Cloud Commander software offers industry-leading transfer speeds of 1 TB / Hour for Exchange Online data, and is also capable of migrating SharePoint Online, Microsoft Teams, and OneDrive for Business between tenants.

Tenant to Tenant Migration Speeds

Installed in your Azure environment, Cloud Commander delivers security and speed. Your data never leaves the confines of your environment, allowing you to maintain control and privacy.

Managed Office 365 Tenant to Tenant Migrations

Quadrotech has specialist teams of migration engineers with extensive experience in migrating, consolidating, and relocating enterprise-scale Office 365 tenants. We offer a fully-managed service to help ensure a smooth transition.

Performing a tenant migration is incredibly complex with many moving parts. An expert team can guide you through the planning stages before executing a rapid migration to help you drastically reduce project timelines.

Contact Quest today and let us help you execute a smooth tenant to tenant migration.