Exchange Online (Microsoft 365) Mailbox to Microsoft 365 Groups Mailbox Migration Guide

This is the complete onboarding task flow for migrating mailboxes from one Microsoft 365 tenant to another Microsoft 365 tenant.

This migration scenario is useful if you want to migrate data from individual mailboxes into shared Microsoft 365 Groups mailboxes. This migration scenario only supports the migration of mail items into the Microsoft 365 Groups.

First time?

This migration guide contains the necessary steps to perform the actual migration, but there are many steps to preparing for migration. If this is your first time performing a migration, we have created a Migration Planning & Strategy Guide to walk you through planning, set-up, and general migration best practices.


MigrationWiz is a migration tool, not a syncing tool. If changes are made at the source after migration, they will not sync to the destination, nor will changes made at the destination sync to the source. We do not have “live” monitoring of changes (as with a sync agent) and we cannot handle scenarios such as conflict resolution without user interaction.

We are not able to support migrations with two-factor or multifactor authentication. 

App password usage is not supported by this endpoint. 

The maximum file size for migration through MigrationWiz varies by migration type and environment, but may never exceed 60GB.

Exchange Web Services (EWS) must be enabled for the mailboxes in the Exchange Online tenant for this migration type

What items are and are not migrated?


  • Inbox
  • Folders
  • Email
  • Contacts
  • Calendars
  • Tasks
  • Journals
  • Notes
  • Server-Side Rules
  • Folder Permissions
  • Post (when the destination is Exchange or Microsoft 365)
  • Calendar acceptance status emails
Not Migrated
  • Safe Sender/Block Lists
  • In-line images in Tasks


Not Migrated

  • Notebooks
  • For Groups documents: anything not in a document library (See SharePoint)

Modern Authentication Requirements

Exchange Online EWS Modern Authentication Requirements (click on this box to expand required steps)

The steps listed below apply to both the source and/or destination tenant when they are Exchange Online, in regards to Exchange Web Services (EWS) in mailbox, archive mailbox, and public folder projects. Use a Global Administrator for the configuration steps.


For setup steps that include images, see under Enabling Modern Authentication for EWS between MigrationWiz and your Exchange Online Tenant in the following KB: Authentication Methods for Microsoft 365 (All Products) Migrations

Important: Failure to perform the steps for your Microsoft 365 endpoints, can result in failed jobs with 401 errors like the following in your project: Http POST request to '' failed - 401 Unauthorized

The administrator account being used for the project needs to be excluded from any MFA/2FA policies or Conditional Access policies that can block access for the administrator account. This requirement does not apply to the items or users being migrated in the project.

Configuring Modern Authentication to work with MigrationWiz for mailbox, archive mailbox, and public folder projects in Exchange Online is now the default method after Microsoft discontinued support for Basic Authentication in Exchange Online after December 2022. The following Microsoft documentation outlines this change in more detail. Should you have additional questions on how this change may impact your tenant, please contact Microsoft to assist with providing that information: Deprecation of Basic authentication in Exchange Online

The Azure Security Defaults must also be disabled in the tenant. (This is often enabled by default for all new Exchange Online tenants and there is no workaround for this requirement). For steps on where to enable/disable the Azure Security Defaults, see Enabling security defaults in the following Microsoft documentation. To disable, set Enable Security defaults to No: Security defaults in Azure AD

Modern Authentication Steps
  • Log in to the Azure AD admin console with a Global Administrator login.
  • Select Azure Active Directory in the Azure Active Directory Admin Center.
  • Select App Registrations, which is found under Manage.
  • Select New Registration at the top of the screen.
  • Give the app a distinct name. You can change this later if necessary.
  • Select the Accounts in any organizational directory button.
  • Under Redirect Uri, select Public Client (mobile & desktop) and set it to urn:ietf:wg:oauth:2.0:oob
  • Click Register.
  • Go back to App registrations.
  • Select the App you just created.
  • In the Overview, you will find a ClientId (aka Application) and Directory (Tenant) ID.
  • Copy both of these to another application, such as Notepad, for use later in this process.
  • Under the Manage menu, select Authentication.
  • Set the option Allow public client flows to Yes
  • Click Save.
  • From the Manage menu, select API permissions.
  • If API permission named User.Read under Microsoft Graph is already present, this can be removed. The Microsoft Graph API is not applicable to this project type and is not used.
  • Select Add a Permission.
  • Select APIs my organization uses

  • Scroll down and select Office 365 Exchange Online

  • Then select Delegated Permissions

  • Select EWS

  • Check the box under EWS for EWS.AccessAsUser.All.
  • Click Add permissions. This permission only allows the OAuth application (MigrationWiz) to be associated with EWS.
      • Important: This does not grant access to all mailbox data.
  • Click Grant admin consent.
  • Click Yes to confirm the settings.
  • In MigrationWiz, select the project that needs to be configured for Modern Authentication.
  • Click the Edit Project menu.
  • Select Advanced Options.
  • Under Support Options enter the ClientID and TenantID information you saved earlier in the following format:
    • If enabling Modern Authentication for the Source:
      • ModernAuthClientIdExport=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
      • ModernAuthTenantIdExport=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
    • If enabling Modern Authentication for the Destination:
      • ModernAuthClientIdImport=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
      • ModernAuthTenantIdImport=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx 
        • Enter the specific ClientID and TenantID for your tenant in place of the xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
        • These options can be entered for either the Source or the Destination, or both, depending on the settings on the tenants.
        • These options need to be configured for each MigrationWiz project that needs to have Modern Authentication enabled.

  • Run a Verify Credentials to confirm that MigrationWiz can connect using Modern Authentication. 
  • Click on the item that was verified. There will be a message in the MigrationWiz Migration Information page that Modern Authentication is being used. This message will show in the “Migration Errors” box; however, it is not an error. This is just a message confirming that Modern Authentication is now active and being used for the connection.

Prepare the Source Environment

Create an Administrator Account

Create an administrator account in Microsoft 365 to be used for migration or use the global admin account for the tenant. The administrator account must have either full access to the user mailboxes or be granted impersonation rights. We recommend using impersonation as it will help reduce the likelihood of the migration being throttled by Microsoft. 

To manually enable impersonation for the source endpoint in your MigrationWiz project:

  • Click on Edit the Project and click on Advanced Options.
  • Click on the Source/Destination tab.
  • Under SOURCE: MICROSOFT 365, make sure the box named Use Impersonation to Authenticate is checked.
  • Click on Save Options.

Important: When impersonation is enabled and a job is requested to be performed in the project, MigrationWiz will attempt to run a remote PowerShell command in the tenant to grant the Application Impersonation role to the admin account being used in the project. In order for this to be successful, the admin account in the project needs to be a global admin to have the required permissions to do so.

Microsoft 365 does not always respond in a timely manner for this process and can sometimes cause the job to fail in the project with an error regarding not having permission to impersonate the user being migrated.

If that is the case or the admin account being used in the project is not a global admin, then manually perform this task in the tenant using the steps outlined under Manually Grant Application Impersonation below (you may opt to proactively perform these steps ahead of time instead of having MigrationWiz do it)

Manually Grant Application Impersonation

Note: The remote PowerShell commands below can take several minutes to complete.

  1. Make sure you are using a global admin account to perform these steps
  2. Click the Windows Start button.
  3. Search for Windows PowerShell (PowerShell should already be installed).
  4. Start PowerShell under an administrator context (right-click -> run as administrator).
  5. Run the following PowerShell commands one at a time:
    Set-ExecutionPolicy Unrestricted$LiveCred = Get-Credential

    Install-Module -Name ExchangeOnlineManagement
    Import-Module -Name ExchangeOnlineManagement
    Connect-ExchangeOnline -ConnectionUri -Credential $LiveCred


    The Enable command may take a long time to run and may error out. If so, wait a few minutes and run it again.
    New-ManagementRoleAssignment -Role "ApplicationImpersonation" -User
  • Make sure to replace "" in the PowerShell command above with the admin account being used for migration.
  • Ignore any errors such as "This operation is not available in current service offer."
  • Ignore any errors such as "The assignment of the management role 'ApplicationImpersonation' [...] won't take effect until user is migrated."



Export the user list to a CSV file

This can be used when bulk-adding users to your MigrationWiz project later. You can copy and paste the user list into the Source and Destination Email columns within your MigrationWiz project dashboard under Add > Bulk Add.

To export the user list:

  1. Go to the Microsoft 365 admin portal.
  2. Click Users.
  3. Click Active Users.
  4. Click Export.
  5. Click Continue.

Be sure to save the csv somewhere you can access it for upload later in the migration.

Prepare the Destination Environment

Create Administrator Account

Create an administrator account in Microsoft 365 to be used for the migration or use the global admin account for the tenant.

Create the Microsoft 365 Group

This step is only necessary if the group does not already exist. Microsoft 365 Groups can be created by either of these options:

Manage group membership

The following actions may be performed to manage group membership before migration.

  • Add members to the Group using the Microsoft 365 admin center.
  • Add migration administrator account as a member of the group.

  • Add migration administrator account as an owner of the group.

MSPComplete Steps

Create the customer

  1. Log in to MSPComplete.
  2. Click the Add button in the top navigation bar.
  3. Click the Add Customer button on the All Customers page.
  4. In the left navigation pane, select the appropriate workgroup and then click All Customers.
  5. Click Add Customer.
  6. Enter the new customer’s information in the Add Customer form. Primary Email Domain and Company Name are required. The rest are optional.
  7. Click Save.
  8. Repeat steps 1 through 4 for each customer you want to add. 


Purchase and apply User Migration Bundle licenses for all the users being migrated. For this migration type, we suggest the User Migration Bundle.

  • User Migration Bundle Licenses have unlimited data available per license.
  • User Migration Bundle Licenses are applied to the customer's users and expire 12 months after their purchase date. 
  • Document, Personal Archive, and DeploymentPro projects are all included when using User Migration Bundle Licenses.
  • This license type must be applied manually.

Purchasing Licenses

  1. Sign in to your BitTitan account. 
  2. In the top navigation bar, click Purchase.
  3. Click the Select button and choose the license type you need.
  4. Enter the number of licenses you want to purchase. Click Buy Now.
  5. Enter a Billing address if applicable.
  6. Click Next.
  7. Review the Order Summary and enter a payment method.
  8. Click Place Your Order.

Applying User Migration Bundle Licenses

  1. Sign in to MigrationWiz at
    • You can either sign in and make sure to select the MigrationWiz button above the email field or sign into MSPComplete page, then click the All Products button and select MigrationWiz.
  2. Select the correct workgroup on the top of the left navigation pane. This is the workgroup that the customer and migration project were created under. Your account must be part of the workgroup and project sharing must be enabled, if the project was not created under your account. 
  3. Click the project that requires licenses to be applied.
  4. Check the box to the left of the email for the user(s) to whom you want to apply a User Migration Bundle license.
  5. Click the More menu (3 stacked lines) at the top of the project page.
  6. Click Apply User Migration Bundle License.

If you have more questions about licensing, including redeeming coupons, or changing categories, see MigrationWiz Licenses.

Purchase User Migration Bundle licenses. User Migration Bundle licenses allow multiple types of migrations to be performed with a single license. They also allow DeploymentPro to be used to configure Outlook email profiles. Refer to these articles for more information:

MigrationWiz Steps

Create the Mailbox Migration project

You will now create the migration project and add your users.

Once a project is set up, you cannot add more users or make changes to the configuration except for advanced options. If you want to add users to the organization, please add them to the source before creating the project or add them manually to the destination. Once the project is created, users will be added to the project automatically from the source endpoint.

  1. Click the Go To My Projects button.
  2. Click the Create Project button.
  3. Create a Mailbox migration. 
  4. Click Next Step.


Endpoints are now created through MigrationWiz, rather than through MSPComplete. The steps for this section outline how to create the endpoints in MigrationWiz.

If you are selecting an existing endpoint, keep in mind that only ten endpoints will show in the drop-down. If you have more than ten, you may need to search. Endpoint search is case and character-specific. For example, Customer will not show up if the search is customer. We recommend keeping a list of endpoints you have created, along with any unique spellings or capitalization you may have used.


Select an existing Microsoft 365 mailbox source endpoint, or create a new one. 

To create an endpoint: 

  1. Click Endpoints.
  2. Click Add Endpoint.
  3. Enter the endpoint name.
  4. Select endpoint type Office 365.
  5. Click the Provide Credentials radio button, and enter the admin account credentials. This should be a global admin account. 


Select an existing destination endpoint for Office 365 Groups mailbox or create a new destination endpoint.

  1. Click New.
  2. Name the endpoint.
  3. Select type Office 365 Groups. If your endpoint is GCC High, select Office 365 (US Government) for your endpoint.
  4. For the URL field, enter the tenant's SharePoint top-level site URL.
  5. Enter the admin account credentials.
  6. Click Add.
  • Click Next Step.
  • Click Save and Go to Summary.

Add User Accounts

Add the user accounts that will be migrated to the project. This may be done in several ways, depending on the size of the project. Steps for each option are in the accordion below, simply click to show the option you select and follow the guidance there.

Small Migrations:

For small migrations, it is easy to add users one-at-a-time using Quick Add. The steps for this are below. 

Larger Migrations:

For larger migrations, we recommend either using the Autodiscover or Bulk Add option.

  • Autodiscover will add all users found on the source tenant. This can then be edited in the project to remove users not being migrated. All users will be added with the source and destination email addresses set to match the source email. This can be changed by using the Change Domain Name button at the top of the project page. If the usernames are changing during the migration, we recommend using the Bulk Add option.
  • Bulk Add uses a CSV containing the source and destination email addresses for the users to add the users to the project. If migrating only a specific group from a tenant, we recommend using the Bulk Add option.
Quick Add
This option allows you to add items one at a time. You have to enter an email address, login name, and password for each user if you didn't enter administrative credentials when setting up the project. You only have to provide an email address if you entered administrative credentials when setting up the project.
Bulk Add

MigrationWiz allows you to bulk import mailboxes into the system.

To import one or more mailboxes:

  1. Sign in to your MigrationWiz account.
  2. Select the Project for which you want to perform the bulk import.
  3. Click Add.
  4. Click Bulk Add.
  5. Follow the instructions on the page.

The Autodiscover process within MigrationWiz can be used to discover items from the Source environment so that they can be imported into your projects.

There are a few requirements in order for this to work:

  • The Source has to be Exchange 2007 or later, or Microsoft 365, or G Suite. If you are using Autodiscover from G Suite, all G Suite domains must be added to the list of domains in the Endpoint.
  • The endpoint on the Source needs to use admin credentials.
  • For mailbox migration projects, the admin account that is specified within the Source endpoint needs to have a mailbox associated with it.
  • The admin mailbox must be listed in the public Global Address List (GAL).
  • The migration project type needs to be a Mailbox migration. For the exact steps to be followed during your migration, refer to the relevant Migration Guide. All Migration Guides can be found on the Help Center site.

One additional item to note here is that there is no way to restrict the IP addresses that the connection will come from.  This means that the steps outlined in our IP Lockdown guide will not apply here.  If your environment requires that any IP addresses be whitelisted, it is recommended that items be added to your project using one of the other available options.

Autodiscover of items will not work while using Modern Authentication

Autodiscovery exposes the following items:

  • For mailbox migration, autodiscovery will list all mailboxes at the Source.

Steps to Run Autodiscover

  1. Navigate to the project you want to import users into.

  2. Ensure that you have created an endpoint for the source project.

  3. Once in the project, on the top navigation bar, click on the Add drop-down, then select Autodiscover Items. This will begin the Autodiscover process.

  4. Once discovered, click on the Import button, to import the items into your MigrationWiz project.

Set the Project Advanced Options

The following option is the most valuable for this migration scenario:

  • Under Filter Folders: ^(?!Inbox$). This RegEx expression migrates the Inbox, but not its subfolders. To migrate both the Inbox folder and Calendars folder, use instead the RegEx expression ^(?!Inbox$|Calendar$). These filters are used to prevent failures, as Groups should only contain an Inbox folder, and possibly a Calendar.  No other folders are supported. This expression must be in the source language, such as ^(?!Boîte de réception$) for French.
  • Important: At the Source/Destination tab in the advanced options of the project, under DESTINATION: MICROSOFT 365, uncheck the box labeled Use Impersonation to Authenticate. This option does not work for Office 365 Groups If you do not uncheck this box, the migration will fail.

Run Verify Credentials

You may verify the credentials of items in MigrationWiz without migrating data or consuming any licenses.

  1. Open the Project containing items you wish to validate.
  2. Select the items you wish to validate.
  3. Click the Start button in your dashboard.
  4. Select Verify Credentials from the drop-down list.

Once complete, the results of the verification will be shown in the Status section.​ 

Notify Users

Notify users that a migration is occurring. Send an email to all users telling them the time and date of the migration.

MX Record Cutover

Change over MX records on the DNS providers' portal. Also, include the AutoDiscover (CName) setting.

Send email to end users to let them know what to expect for their Outlook profile reconfiguration. 

Run Migration

You are now ready to run the migration. 

  1. Select the users.
  2. Click the Start button from the top.
  3. Select Full Migration.
  4. Select to migrate Mail only.
  5. Click Start Migration.

Run Retry Errors

Look through the user list and click any red "failed migration" errors. Review the information and act accordingly. Each error logged represents an item that was not migrated. MigrationWiz contains a mode in which you can resubmit the migration to retry failed items. This mode of operation is always free of charge. You may only submit mailboxes in this mode only if they satisfy all of the following conditions:

  1. The last migration pass was completed successfully.
  2. The mailbox contains at least one error.

If your mailbox does not satisfy these conditions, you will receive a warning when submitting the migration in this mode and your request will not be fulfilled.

To submit one or more mailboxes in retry mode, perform the following steps:

  1. Sign into your MigrationWiz account.
  2. Click the Go To My Projects button.
  3. Select the project that contains the mailboxes that you want to retry.
  4. Select the mailboxes that have migration errors.
  5. Click on the Start button.
  6. Select Retry Errors from the menu.
  7. Click the Retry Errors button.

When errors are repaired, they will disappear from the error log. Some errors may not disappear if the Source item was not reprocessed (due to filters, for example), has been deleted or moved, or if the item failed again. 

If problems persist, contact Support.

Post Migration

  • Show users how to access the Microsoft 365 Group; this will appear in their Outlook, under Groups.
  • Click the pie chart icon in the MigrationWiz dashboard to receive an email containing all the project migration statistics.
Was this article helpful?
0 out of 1 found this helpful