Google Groups to M365 Shared Mailbox Migration Guide


This article will guide you through the for migrating from Google Groups to Microsoft 365 Shared Mailbox.

You can easily set up a mailbox project and leverage the MigrationWiz solution to migrate your members, conversations, and attachments from Google Groups to your desired Microsoft 365 Shared Mailbox.


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.


It is important to note the following prerequisites in order to have a smooth migration project.

  • The source administrator must have a valid Google Vault license before proceeding with the migration project.

  • Both Shared Mailboxes and members at destination are provisioned by customer beforehand. MigrationWiz currently does not auto-provision the Shared Mailboxes and members at the destination.

  • Google Groups requires “Conversation History” to be enabled for conversations to be kept. A collaborative inbox has “Conversation History” enabled by default. However, it is recommended to verify this in the Group’s setting.


The following are some of the limitations for the migration of Google Groups to Microsoft 365 Shared Mailboxes. Some of the limitations are an inheritance from the APIs used as well as the capabilities of the current destination.

  • External members from the source are not migrated as Microsoft Shared Mailboxes do not support external members.

  • Groups settings (posting policy, member moderation, member privacy) are not migrated as Shared Mailbox instances do not support these settings.

  • A nested Group which is a member of another Groups will not be migrated.

  • Conversation tags like “Star”, “Abuse”, “Report”, “Locked” are not migrated due to lack of data from the source extract. The conversations are migrated.

  • Collaborative inbox features like “Assign to me”, “Assign to someone”, “Mark as completed”, “Mark as duplicated”, “Mark as no actions” are not migrated as these are not supported in Microsoft Shared Mailboxes. The conversations are migrated.

  • Conversations under “Moderated” or “Pending” are not migrated due to lack of data from the source extract.

  • In MigrationWiz, Google Groups messages are exported and migrated individually to the Shared Mailbox destination, while the Google Groups app shows the number of threads and messages within the thread. Therefore, there would be a mismatch of migrated item counts between what is indicated in MigrationWiz and Google Groups itself.

  • In MigrationWiz, Google Groups messages are exported and migrated individually to the Shared Mailbox destination, therefore, messages are shown as individual emails instead of it’s original conversation thread format.

    • To prevent encountering this issue, choose one of the following:

      • It is recommended that user select only 3 line items per run, or

      • User should set “Advance Option>Performance>Maximum number of concurrent migrations” to 3, or

      • User should create multiple projects to accommodate all the line items.

        MigrationWiz leverages PowerShell to migrate the project line items, hence, there is an inherited PowerShell concurrency limitation of 3 line items per run. Selecting more than 3 line items may result in a timeout error.

Which Items Are and Are Not Migrated

What is migrated

  1. Google Groups Members

    • Google Groups members' roles and permission (Owner, Manager and Member) are mapped as “Full Access” in Microsoft Shared Mailbox

  2. Google Groups conversation

    1. Conversation metadata

    2. Conversation attachments

    3. Conversation labels

What is not migrated

  • Google Groups settings (Posting policy, members moderation, member privacy)

  • Collaboration Inbox features like ‘assignment of task’ and ‘status of tasks’

  • Conversation tags like “Star”, “Abuse”, “Report”, “Locked”

  • Conversations marked under “Moderated” or “Pending”

  • External members

  • Any nested Group which is a member of another Group

Prepare the Source Environment

Google Groups Endpoint


This endpoint requires your tenant service account to be set up and Google APIs be enabled. 


  • Subscription to Google Cloud Platform

  • Google Super Administrator account

  • Ability to set up a service account on the G Suite tenant

  • Service account must be set up before the MigrationWiz project is created

  • Administrator must have Google Vault access privilege

Create a Google Project

  1. Go to the Google Cloud Platform (GCP) Console and sign in as a super administrator. Choose one of the options below:

    • If you haven't used the Google Cloud Platform Console before, agree to the Terms of Service and click Create Project.

    • If you have used Google Cloud Platform Console before, at the top of the screen next to your most recent project name, click Down to open your projects list. Then, click New Project.

  2. Enter a project name and click Create.

Enable APIs for Service Account

  1. From the Google Cloud Platform Console, click Menu () > APIs & Services > Library.

  2. Enable the following APIs by selecting the specific API and clicking Enable. Repeat for each API.

    • Groups settings API

    • Google Vault API

    • Admin SDK

Make sure that the respective services are enabled within the Google tenant. You can control services for your users by following the instructions on this page: G Suite and Google Services Access.

Create Customer Tenant Service Account

  1. From the Google Cloud Platform Console, click Menu > IAM & Admin > Service accounts.

  2. Click Create Service Account and enter a name.

  3. Click Create.

  4. Assign the role of Owner to the new Service Account by selecting Owner from the Role drop down menu.

  5. Click Done.

  6. You will now be returned to the Service Accounts page. 

  7. On the Service accounts page, click the vertical ellipsis under the Actions column for the service account created above, and click on Manage Keys.

  8. Click + Add Key.

  9. Click Create New Key.

  10. Make sure that JSON is selected as the Key Type.

  11. Click Create.

  12. Click Close.

    • Make sure that you download the key as a JSON file and make a note of the name and location of the file. This JSON file will be used when setting up the migration endpoint in the mailbox migration project.

    • The JSON file must contain information in the following fields: “type”, “private key”, and “client email”. If these mandatory fields are empty, the file upload during endpoint creation will fail.

  13. From the service account that was set up in Step 3 (Create Customer Tenant Account):

    • Find the Unique ID field for that service account by clicking the Column Display Options “|||” button in the right upper corner above Actions.

    • Select the Unique ID checkbox.

    • Click Ok.

    • Copy the unique ID number. This is the Client ID number that will be used in a later step.

      • This Client ID should be considered similar to Administrator account passwords and handled securely.

Setting the Scopes for the Migration

From the Google Admin Dashboard:


  1. Click on Security

  2. Click on API Controls

  3. On the API Controls page, locate section Domain-wide delegation

  4. Click on Manage domain-wide delegation

  5. Click on Add new

  6. In the client Name field, enter the Service account Unique ID

  7. For OAuth scopes, enter the scopes listed below:






  8. Click Authorize.

Assigning Google Vault privileges

  1. User must be a Super Administrator user, and signed in as one

  2. Sign in to Google Admin Console

  3. In the Overview page, click on Admin Roles

  4. Click on Create a New Role

  5. Enter the Name and Description for the role, click Continue

  6. Find and expand the list on Google Vault, select the following:

    1. Manage Matters

    2. Manage Searches

    3. Manage Exports

    4. View All Matters

  7. Click Continue

Prepare Destination Environment

Microsoft 365 Endpoint


  1. Set up user accounts on the destination Office 365 tenant and assign licenses. These can be created in several ways:

  2. Create an administrator account in Office 365 to be used for migration or use the global admin account for the tenant. The minimal service account requirements are either full access rights to the mailbox or impersonation rights. We recommend using impersonation over delegation because it is Exchange Online. For specific steps to set impersonation manually, see Impersonation and Delegation.

  3. Test that the administrator can access user mailboxes.
    Test access to the addresses, not to the addresses. Make sure that the account is attached to each mailbox in Office 365. By default, it should be attached, but if not, it will need to be added as an alias to each account. This can be done through the Office 365 admin portal or via PowerShell scripts. Read the Verify mailbox accessibility using EWS article for more information.

BitTitan now supports Modern Authentication for Microsoft 365 endpoints used for Mailbox migrations. Modern Authentication provides a more secure authentication mechanism for registered applications to connect to Azure Active Directory and Microsoft 365. 

Authentication Methods for Microsoft 365 (All Products) Migrations

MigrationWiz Steps


The Google Groups to Microsoft 365 Shared Mailbox migration is supported by the Mailbox License and User Migration Bundle (UMB) license types.

Purchasing a license

To purchase 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.

​​Licenses are released once payment has been received:

  • If you purchase via credit card, licenses will be available immediately upon payment.

  • If you purchase via wire transfer (100+ licenses), licenses will be available once payment has been received and accepted.

  • We do not accept purchase orders, because of processing overhead.

In both cases, you will be notified by email that payment has been accepted and licenses will be available in your account upon notification.

For more information on licensing, including coupon redemption and other licensing types, see our Licensing FAQ.

Set up a Mailbox Migration project

  1. From MigrationWiz dashboard, click Go To My Projects.

  2. Click Create Project.

  3. Select a Mailbox migration type. 

  4. Click Next Step.

  5. Enter a project name and select a Customer from the list.

    1. If the customer hasn’t already been created, you can do so here.

    2. To create a new customer, click New, provide required details including primary email domain and company name, and click Save.

  6. Click Next Step.

  7. Select Google Groups endpoint from the source drop-down menu.

    • If an endpoint has not been created, click New.

      1. Enter a name in the Endpoint Name field.

      2. Select Google Groups from the Endpoint Type drop-down menu.

      3. Upload the JSON file for your service account setup.

      4. Provide a valid super administrator email address for G Suite account which matches the end user domain.

  8. Select the Office 365 destination endpoint from the destination drop-down menu.

    • If an endpoint has not been created, click New.

      1. Enter a name in the Endpoint Name field.

      2. Select Office 365 from the Endpoint Type drop-down menu.

      3. Select Provide Credentials or Do Not Provide Credentials as needed.

        1. If you select Provide Credentials, the form expands to present more fields for username and password. The credentials will be used by MigrationWiz to access the service selected. In most cases, you must provide credentials for an administrator account on those services, as this will enable MigrationWiz to have full access to the cloud service.

        2. If you select Do Not Provide Credentials, then MigrationWiz will request credentials from end users before a migration can be started. This may slow your migration, as you are now dependent on the end users to provide these credentials.

  9. Click Save, Go to Summary then click Save Project.

Add Accounts (Items)

Add the accounts that will be migrated, which are also referred to as items, to a project using one of the following options:

  • Quick Add: This option allows you to add items o​ne at a time. Provide an email address for source and destination for each.

  • Bulk Add: This option allows you to add multiple items at once by copying and pasting from a spreadsheet or by importing a CSV file. The domain names at the Source and at the Destination might be different. Make sure to provide the right information in the project. If they are different, it's best to modify these in your CSV file, and then use the Bulk Add feature to import the users into the dashboard.

Advanced Options

The following advanced options may be useful for your migration. 

Advanced options under Support tab

  • RecipientMapping - Use this advanced option to map the source email addresses to destination. Right part is a RegEx applied to the recipient email address. You can use more than one remapping expression.

  • UseHashMapRecipientMapping - Use this advanced option together with Recipient Mapping to increase performance when mapping large numbers of recipients

  • ModernAuthClientIdImport - Modern authentication client ID support for tenants not using legacy authentication (basic authentication). You would have to setup the app in your AAD portal to get the client and tenant ID. Authentication Methods for Microsoft 365 (All Products) Migrations

  • ModernAuthTenantIdImport - Modern authentication tenant ID support for tenants not using legacy authentication (basic authentication). You would have to setup the app in your AAD portal to get the client and tenant ID. Authentication Methods for Microsoft 365 (All Products) Migrations


Verify Credentials

  1. Open the project containing the items you wish to validate​.

  2. Select the line items you wish to validate.

  3. Click the Start button in your dashboard.

  4. Select Verify Credentials from the drop-down list.

  5. Once complete, select the Status section and view the results of the verification.

Performing a Migration

Trial migration

  1. Select the line items you wish to migrate

  2. Click the Start button from the top

  3. Select Trial Migration

  4. Click Start Migration.

Pre-Stage pass

  1. Select the line items you wish to migrate

  2. Click the Start button from the top

  3. Select Pre-Stage Migration

  4. Under the Migration Scheduling section, from the drop-down list, select 90 days ago

  5. Click Start Migration.

Full pass

  1. Select the line items

  2. Click the Start button from the top

  3. Select Full Migration

  4. Click Start Migration

Run Retry Errors

Look through the user list and click any red "failed migration" errors. Review the information and act accordingly.

If problems persist, contact Support.

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