4 quick tips to make your Microsoft 365/Office 365 tenant to tenant migration a success

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Preparing for a Microsoft 365 tenant to tenant migration as part of a business merger or acquisition? These quick tips will help make the process as smooth as possible and ensure your migration is a success!

In a year that has seen many organizations rapidly transition to new methods of collaboration and fully remote work, technology has played a critical role—and accelerated many a cloud migration project. According to Flexera’s 2020 State of the Cloud Report, 70% of SMB workloads and data will reside in a public cloud like Azure within the next 12 months.

With the scale beginning to tip towards organizations that have migrated to the cloud vs those that haven’t yet, IT admins are now more likely than ever to encounter a Microsoft 365 (formerly Office 365) tenant to tenant migration in the context of a business merger or acquisition. And merging two Microsoft 365 tenants comes with its own unique set of challenges.

To help make the process as smooth as possible and guarantee your tenant to tenant migration is a success, read on to find our quick tips for migrating Microsoft 365 data during a merger or acquisition!

These quick tips will help ensure your Microsoft 365/Office 365 tenant to tenant migration is a success:

  1. Make sure both tenants are organized and up to date as part of your pre-migration planning

    Tidy tenants make it easier to decide which resources are worth bringing, and staying on top of ownership and permissions will put you a step ahead when it comes to ensuring data security at your new destination.

  2. Create an inventory of what you have and what you need to bring

    Having a detailed inventory of both environments makes it easier to estimate the effort required and define the scope of your migration.

  3. Identify and fix potential issues ahead of time to ensure a successful tenant to tenant migration

    Identify and fix potential issues before starting your migration to minimize the downtime and potential impact on your users.

  4. Include everything in the migration process that your team will need

    The integrated nature of Microsoft 365’s productivity suite means you need to bring more than just your SharePoint content. In particular, migrating Microsoft Teams data has become more critical to ensuring a seamless transition.


Planning an Office 365 migration? Whether your Office 365 migration is still in the planning stages or well underway, this checklist is an invaluable resource when it comes to avoiding costly mistakes and ensuring everything runs smoothly from start to finish.

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The ultimate Office 365 Migration Checklist


1. Make sure both tenants are organized and up to date as part of your pre-migration planning

One of the best things you can do to ensure a successful merger or acquisition is something you should already be doing on a regular basis: making sure your Microsoft 365 environment(s) are organized and up to date.

Microsoft 365 introduces new collaboration concepts, like Microsoft Teams and Microsoft 365 Groups, that empower end users to create the tools they need without having to go through IT.

According to Microsoft MVPs (and ShareGate!), you should definitely keep these self-service features enabled. Giving users more freedom helps drive adoption of new tools and makes it less likely that people will turn to other solutions outside your environment.

However, everything scales a lot faster in the cloud. Which means that you need to guide proper usage of the tools to avoid ending up with multiplying groups and teams and to keep organizational data secure on an ongoing basis.

Twenty-five percent of Microsoft 365 groups are inactive and 7.3% have no valid owner.

Benjamin Niaulin (@bniaulin), according to data from ShareGate Apricot, our Teams management tool Tweet this

If you really want to ensure a seamless tenant to tenant migration, we recommend that you do the following pre-migration (and after that on a regular basis):

A tidy environment makes it easier for users to find what they’re looking for, fast. It will also make your life a lot easier when you’re trying to decide which resources to bring with you in the migration. And, by staying on top of group ownership and external sharing links, you’re already one step ahead when it comes to ensuring data security at your destination.


2. Create a detailed inventory of what you have and what you need to bring

As an IT admin, there are some key decisions you need to make before starting your migration, such as: Which tenant will be the source environment and which will be the destination? What will the scope of your migration project be? (i.e. what do you actually need to bring?) In order to answer questions like these, you need to have a clear understanding of what each tenant currently looks like.

For each tenant, ask yourself:

  • Do you know where all of the information is stored?
  • Do you know the hierarchy of those data repositories?
  • Do you know their sizes?
  • Is the data actually being used?
  • What workloads are being used?

A tenant to tenant migration is a great opportunity to take stock of all the existing content that’s involved—and a chance to start off your newly-merged Microsoft 365 tenant on the right foot. As you identify existing content, you might find duplicate content, content that’s no longer up-to-date or valid, or content that can be archived and deleted.

That’s why making a detailed inventory is a crucial part of planning any successful migration.

An inventory should include information like:

  • The amount and type of content
  • Where that content is stored
  • Who has access to that content
  • What actions you might need to run on certain items

Having an inventory of both environments also makes it easier to estimate the effort required and make an informed decision about which will be your source and target tenants.

Here at ShareGate, we’ve come up with an inventory strategy that we like to call RMR: Remove, Migrate, and Rebuild. It’s an easy model to help differentiate between what you don’t need, what you plan migrating as-is (or with a few minor tweaks), and what you plan on rebuilding at the destination.

Once you have a better understanding of the broad scope, you can dig down into the specifics for each data type and make an informed decision about what you actually need to migrate and what you can leave behind.

And once your tenant to tenant migration is completed, it’s a good idea to continue keeping an active inventory of what you have to maintain and uphold your governance rules over time.


3. Identify and fix potential issues ahead of time to ensure a successful tenant to tenant migration

There’s another part of planning that’s equally important to ensure your tenant to tenant migration runs smoothly and has the least possible impact on end user productivity: identifying and fixing potential issues before you get started.

After all, if you’re going to go to the trouble of migrating something from Tenant A to Tenant B, you want to make sure that everything makes it to the destination with all of its access and permissions intact.

Here’s a list of some things to look out for that could potentially cause issues during a migration to help get you started:

  • URLs (file paths) and file names
  • File sizes
  • Character limitations
  • Custom solutions
  • Branding
  • InfoPath
  • Workflow state and history
  • Permissions (do you have access to all the files?)
  • Folders with more than 5000 items
  • Unsupported site templates
  • Orphaned users
  • Checked out files
  • Unsupported list templates
  • File extensions

For example, our data tells us that, on average, 5,406 items in SharePoint Online have unique permissions. But most migration tools have problems moving custom permission levels to SharePoint—meaning you would have to manually recreate those permission levels on the destination SharePoint sites.

On average, 5,406 items in SharePoint Online have unique permissions.

Benjamin Niaulin (@bniaulin), according to data from ShareGate Desktop, our SharePoint migration tool Tweet this

That’s a lot of potentially broken permissions! Instead, Microsoft recommends moving users and groups to the default SharePoint permission levels pre-migration, or building out a plan for creating the custom permission levels and fixing permissions post migration.

There are also considerations to take into account for migrating business process and workflows from one tenant to another. In case you haven’t heard the news,  Microsoft has retired SharePoint 2010 workflows (and confirmed that SharePoint 2013 workflows will be deprecated at some point in the future).

So, you need to be aware of any legacy SharePoint workflows in either environment as you plan for your tenant to tenant migration. Where are they located? What do they do? Are any of them stopping your migration project? And if so, can you rebuild them as SharePoint 2013 workflows or, better yet, transition to Power Automate flows?

Depending the unique needs of your organization’s migration project and the current state of the Microsoft 365 tenants involved, there are other things you might want to plan for and take into account.

For example, if one (or both) tenants have a top-down infrastructure and you want to be able to use Microsoft Teams at your destination, you’re going to have to promote all of your subsites to top-level site collections, first.

Taking the time to identify and fix potential issues now will really pay off in the long run—minimizing the downtime and potential impact on your users, reducing risk, and coming out the other side with a destination environment that’s a whole lot easier to manage and secure.


4. Include everything in the migration process that your team will need

While you do want to be smart about the scope of your migration project in order to minimize downtime, you also want to make sure you don’t leave behind anything your users need to do their work. And since this is a Microsoft 365 tenant to tenant migration (not a migration from on-prem to the cloud), that means you probably need to migrate more than just the content in SharePoint Online.

In particular, Microsoft Teams has become central to the Microsoft 365 user experience thanks to a steady stream of new features, an easy-to-use interface, and seamless integration with other Microsoft tools. According to our data, 60% of Microsoft 365 groups have a Microsoft Teams team attached.

Sixty percent of Microsoft 365 groups have a team attached.

Benjamin Niaulin (@bniaulin), according to data from ShareGate Apricot, our Teams management tool Tweet this

With the content created in Teams now more valuable than ever, the ability to migrate this data as needed is no longer a nice-to-have; in the context of a merger or acquisition, migrating Microsoft Teams from one tenant to another is a critical process to ensure user workflows also transition to the destination environment seamlessly.

But migrating Microsoft Teams can be challenging, largely due to the fact that most Teams data isn’t stored in Teams. Some of it does live in SharePoint Online, in each team’s associated SharePoint site. But it also lives in all of the following locations:

  • SharePoint team site: Files and folders stored in the team document library or shared in a channel, external emails sent to the team, the team’s wiki page, and each channel’s OneNote assets.
  • Exchange team mailbox: Group chat and channel chat conversation history, team mail, and contacts.
  • Exchange mailboxes of individual users: Private (1:1) chat conversation history, voicemails, and calendar meetings.
  • OneDrive for Business of individual users: Files attached to private chat sessions, or a chat during a meeting or call, are uploaded and stored in the OneDrive account of the user who shared the files.
  • OneDrive organizational document library: Users’ personal OneNotes.
  • Azure (using Blob storage): Images and media (except for GIFs) shared in chats.
  • Stream: Meeting recordings.
  • Third-party storage provider: If your organization allows users to store files with a third-party storage provider, either through tabs or other partner apps, that information is stored directly in the system used by the partner.

Before starting your tenant to tenant migration, make sure you understand how users are currently collaborating in Microsoft 365 so you can be sure to bring everything they need to their new destination. And with the continuing surge in Teams usage, we highly recommend you take a look at what they’re going to need from their Microsoft Teams-based workflows.

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