Performing a successful Microsoft 365 Tenant Migration for M&A

Microsoft 365 Tenant Migrations for Mergers & Acquisitions

By Matthew Maher  •  August 16, 2022  •  1056 Views

Microsoft 365 Tenant Migrations for Mergers & Acquisitions

Microsoft 365 Tenant-to-Tenant Migration Step by Step:

Over the past few years, Mergers & Acquisitions (M&A) space has increased to a point where most consulting firms have a Microsoft 365 tenant migrations service offering. This highlights the fact that tenant merger is a complex area that requires more than just a tool to be completed successfully. Successful migration depends on many things going right and understanding that merging tenants is more than just data migration. Here are a couple of areas that we feel are vital to the success of Office 365 tenant-to-tenant migration. 


The first, and most crucial step, to any migration is the planning phase where we perform inventory, assessments, and strategize. We typically inventory both the source and target from macro-level container size all the way down to which users are VIPs. During this inventory, we look for usage trends to help us understand which Microsoft 365 services are actually being used and what needs to be archived or is just a lift and shift.  

We also need to plan for workloads or settings that tools cannot move (e.g., Microsoft Forms, Power Automate, etc.). Our strategy for these services could be one of many. We could plan for user communication detailing why we are not moving the service, or we could build into our project plan manual intervention around these services. But ignoring them just because a tool cannot migrate is short-sighted and will commonly crop up during your day one activities. 

Change management and adoption strategy 

A tenant migration is more than just the technical pieces about moving files, e-mail, and chat messages. It is important to not overlook some of the most crucial pieces like user-experience changes, Day 1 helpdesk load, and training of new services or processes. All of these are parts of the success of tenant migration. At Netwoven, we call Change Management and Adoption in parallel to the technical assessment and planning that our team does, so that we do not lose sight of them. 

Once we understand the change users will go through, it is time to plan for assets to help with the change. We find that some of the most used artifacts in a tenant migration are:  

  • FAQs (Frequently Asked Questions) around common issues 
  • Day 1 experience videos 
  • Transparent and accessible timelines 
  • Dedicated help channels (Teams bot, Yammer group, Migration Issues lists) 

Pilot migrations, and determining the success criteria 

In any migration, it is important to run pilots to confirm your run books, bolster FAQs from real-world issues, validate throughput calculations, and more. But you do not want to run pilots just to run pilots, make sure to define your success criteria first. At Netwoven, we like to make sure the pilot is a dry run of actual migration, so if you are expecting 1TB of throughput over a weekend, make sure to measure it.  

Another great reason for pilot migrations is to test your helpdesk response and FAQs. We calculate ~10-20% of users will interact with a help medium during the first week. During your pilot, you can validate the assumption by seeing how many people reach out. Also, when they reach out, make sure to track what issues they are having and what the resolution is. This will act as your sample of what to expect from broader rollouts.  

Efficient execution 

During the project, your team will be putting in long hours completing their day jobs and the migration prep work. It is important to find efficiencies where you can during this time and during the time of cutover. Although it might seem smart to bring the entire project team into daily status calls, the time commitment of these calls takes the core team away from their work. Instead, try to split your meetings out per workstream (e.g., Collaboration, Messaging, Identity). 

Another execution tip is to prepare scripts that scale. Too often we handle trivial things through the UI (User Interface), a missing proxy address here, site collection quota there. But it does not scale when we start to do thousands of sites and tens of thousands of people. To be efficient in the task, we like to spend the extra ten minutes to script the change so that we can run it again much faster when we need to in the future.

Transparency in reporting 

Always remember the audience of a report when reporting on status. Executives love to see the simple macro-level reports from tools like BitTitan: 

Microsoft 365 Tenant Migrations for Mergers & Acquisitions

But technical folks appreciate the details in an Excel report or the richness of PowerBI reports. Ones that they can manipulate to answer questions like “How many mailboxes over 50GB were moved in Wave 1 vs Wave 2”. For these folks, Netwoven puts together PowerBI reports like this one to show trend lines and allows the recipient to filter and pivot. 

Microsoft 365 Tenant Migrations for Mergers & Acquisitions

Support after migration 

The last phase of Office 365 tenant-to-tenant migration for mergers and acquisitions is support. After the migration weekend, your support desks will be flooded with calls, emails, IMs, and drop by. Planning for this and augmenting your normal support desk is critical. Some customers bring on hundreds of call center operators to handle the Week 1 activities. The positive thing about these operators is that they can be used for a 2–3-week period and then rolled off. The negative thing is they are only as good as the script they are given. So, make sure to spend the time drawing out the decision tree they need to follow for each type of call.  

Another way to support users after the migration is through guides and work aids. These assets can be created in advance with the exact screenshots that users will see on their computers. Distributing these a few days before the cutover can reduce the support load on Day 1. 

We hope you found this blog useful in learning the various steps involved in successful Microsoft 365 tenant-to-tenant migrations for Mergers & Acquisitions. Please reach out to us so that we can put our decades of experience and expertise in tenant migration services and Microsoft technologies to help you in your organization’s Digital Transformation journey. 

By Matthew Maher

Matt Maher is a technical director with Netwoven who has been working with Fortune 500 companies implementing large scale enterprise systems for the last 15 years. Matt is an early member of the Netwoven team and has helped grow Netwoven from it’s infancy to the current stages. Matt is passionate about blending productivity and security to enable modern workplaces. His leadership and expertise have helped companies build secure, highly effective solutions and applications. Matt holds a BS in Computer and Informational Sciences from the University of Massachusetts.

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