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Office 365 Tenant Migration: How to Migrate Exchange Mailbox Permissions

Jun 11, 2020 by Mike Weaver

The Exchange logo moving from one cloud to another, representing an Office 365 tenant migration.

Quadrotech recently released an enhancement to support folder level permissions in Office 365 tenant migrations. This expands our support to automatically migrate the three types of Exchange Permissions. All of these have end-user impacts, and this development continues our goal of reducing end-user disruption in cross-tenant migrations.

We often get asked, “Do you migrate delegates in tenant to tenant migration projects?”. Although we have been able to answer “yes” to this for quite some time, the problem is deeper.

When people ask about delegates, they’re typically referring to any shared permissions. Let’s review the three types, and how we handle them within our Cloud Commander software. We will then spin off into sub-articles on each topic in more detail.

Mailbox Delegates

The mailbox delegate process is one of the oldest, user-driven ways for users to provide access to their mailbox. This also includes the ability to have calendar invites sent to a designated user – a common setup for workers that have their calendars managed by someone else.

Reporting on Mailbox Delegates, and setting it, can be tricky. Here at Quadrotech, we have you sorted and can read delegates, their access level, and reapply them in the target system during the migration.

Screen shot showing how and where to access mailbox delegates.

Full Mailbox Permissions

Another option for providing access is done at the Mailbox Level. This is very common in Shared Mailboxes. These are permissions that have been set by an Administrator, with many organizations using automation tools to control access. There can be several options selected.

These permissions can be viewed in the Admin Center UI and in PowerShell. However, collecting them, mapping them to the new system, and then applying them can be quite a pain. Again, we have you covered with our tenant to tenant migration service.

Folder Permissions / Calendar Permissions

Finally, we have Folder Level Permissions. We have launched this feature with several sub-options as well. Although there are many use cases for users setting folder level permissions, the most common is the Calendar sharing option. In the modern version of Outlook, sharing a calendar is a breeze. Now we can copy these over in the migration.

The options allow you to migrate only Calendar Folder Permissions, Top Level Permissions, or all Folder level Permissions.

Screen shot showing how to access Exchange Folder and Calendar permissions.

If you are looking for more detail on Outlook Folder Level permissions, well… this is another topic.  You can view this in more detail in this separate post.


Migrating Mailbox Permissions, Delegates & Folder Permissions can be a big concern in tenant to tenant migrations. This release completes the automation offering for migrating mailbox permissions.

If you have a an upcoming tenant migration and would like to learn about our managed services, please get in touch today.