Office 365 Tenant Migrations

by | Jan 26, 2018 | Infrastructure | 0 comments

There are times where administrators may find themselves challenged to migrate from one Office 365 tenant to another.  There are many factors that can create massive hurdles for any migration, and those can be even more significant with Office 365 migrations.

Three key areas that can be challenging include: data migration, domain migration, and Azure AD Connect.

Data Migration

The first challenge many will face is realizing that there currently isn’t a native solution to migrate data from one tenant to another.  There are a few other options available:

  • Depending on the size of the tenant you could shut down all services, manually export and migrate date between tenants
  • You could export all historic mail to a PST and import it to the new tenant, then during a cutover window, shutdown services and export all left over mail. You will need to manually copy SharePoint data in a similar fashion.
  • Use a 3rd party solution to copy data from one tenant to another. 3rd party solutions allow you to copy all with less manual and administrative effort.  Most of the time, this is the simplest option.

Domain Migration

Migrating a domain between tenants can be a very simple and easy task…unless you are using ADFS or Azure AD Connect.  The use of Azure AD Connect will tie the domain to your local Active Directory and Office 365’s Azure AD.  Each object that is synchronized will have an attribute applied to designate it as an on premises user.

To break this relationship is at times as easy as running a PowerShell command to disable the directory synchronization.  However, if you plan on cutting the domain over to a new domain it will take time to replicate this change to every object in Azure AD.  This means as soon as you execute the PowerShell command (Set-MsolDirSyncEnabled -EnableDirSync $false) a process will run to change the synchronization attribute on every object that was previously synchronized. Depending on the size of the environment this could take 10 minutes or 48 hours.   Planning for this is hard, and the worst case scenario of 2+ days should be taken into account.

In order to add and authorize a domain to Office 365 it cannot exist anywhere else.  This has become a problem in even moving to Office 365 because of things like Power BI which allow anyone to create an account.  We discussed this topic in a prior blog on Tenant Creation.

Azure AD Connect

Beyond just disabling Azure AD Connect, the connectors for synchronization will be changing and cause concern.  Often it is a better solution to build a new Azure AD Connect server to connect to the new tenant but you will only want to do this once the new tenant has the domain validated for User Logins.

Creating a second / separate Azure AD connect server allows you to spend the time appropriately migrating any custom configurations ahead of the migration.

Any migration can have a lot of hidden pitfalls.  Office 365 tenant migrations add their own challenges to the mix, but hopefully this blog helps you prepare for some of them.  Any migration between companies contains several data points that need to be collected, analyzed and prepared for to ensure a successful migration.  If you find yourself about to start planning a migration and need some assistance e-mail We are happy to help!