Hosted Exchange to Exchange Online (Microsoft 365) Migration Guide

This article will guide you through the steps for migrating mailboxes from a Hosted Exchange Provider to Microsoft 365.

App passwords are not supported for the Microsoft 365 endpoint. We are not able to support migrations with two-factor or multifactor authentication. 

There are some tools and resources that will make the migration easier.

MigrationWiz

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.

MigrationWiz supports the capability to share migration projects across a Workgroup. When the Project Sharing feature is turned on, all Agents besides those who are Inactive can view all migrations projects. 

First Migration?

We’ve created a guide on scoping, planning, and managing the migration process for your use. If this is your first migration, we recommend reading this guide carefully.

Prerequisites

It is important to highlight and meet the following prerequisites for a smooth migration project.

Licensing

We recommend that you purchase User Migration Bundle licenses for this migration scenario. User Migration Bundle licenses allow the performance of multiple migrations with a single license. For questions on licensing, visit MigrationWiz Licenses.

To use your license by following the next steps:

  1. Purchase Licenses.
  2. Create a Customer.
  3. Apply Licenses.
  4. Review Considerations.
Purchase Licenses Create a Customer Apply Licenses Considerations

Purchase licenses by following the steps below:

  1. Sign in to your BitTitan account. 
  2. In the top navigation bar, click Purchase.
  3. Click the Select button and choose User Migration Bundle licenses.
  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.

Limitations

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

Migrated Items

Which items are migrated?

Migrated items vary by version of Exchange. The following list is for Exchange Server 2010 SP1+. If you are using an alternate version of Exchange, please refer to the Migrated and Not Migrated Items list and check for your version of Exchange.

  • Inbox
  • Inactive inboxes
  • Folders
  • Email
  • Contacts
  • Calendars
  • Tasks
  • Journals
  • Notes
  • Post (when the destination is Exchange or Microsoft 365)
  • Personal Folder and Calendar Permissions (Exchange 2013 and 2016 only)
  • Server-Side mailbox rules
  • Client-Side mailbox rules for Outlook (Exchange 2013 and 2016 only)
  • Automatic Replies (Out of Office Messages) (Exchange 2013 and 2016 only)
Which items are not migrated?

Not migrated items vary by version of Exchange. The following list is for Exchange Server 2010 SP1+. If you are using an alternate version of Exchange, please refer to the Migrated and Not Migrated Items list and check for your version of Exchange.

  • Email templates
  • Email flags (if the destination is G Suite)
  • Safe Sender/Block Lists
  • Mail Settings
  • Standalone documents stored in Mailbox Folders or Public Folders (Example: IPM.Document item types)
  • System Public Folders
  • StickyNote folders

For additional features and limitations, please visit MigrationWiz: Migrated and Not Migrated Items.

Important

When Exchange is the source, keep in mind the following points:

  • If an account exists in the destination and matches the UPN prefix of an account with Calendar Permissions in the Source before submitting a migration, Calendar Permissions will be migrated (except for Resource Calendars) but the Resource Calendars permissions are not migrated.
  • If an account does not exist in the destination that matches the UPN prefix of an account with Calendar Permissions in the Source before submitting a migration, Calendar Permissions are not migrated.

Exchange Questions and Troubleshooting

Our Exchange Mailbox FAQExchange Migration Setup and Planning, and Exchange Mailbox Migration Troubleshooting guides contain a number of common questions and concerns, along with more information, guidance, and steps to resolve issues such as throttling.

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

DeploymentPro & DMA

DeploymentPro currently can only officially be used with migration projects where Microsoft 365 is the Destination. If using DeploymentPro with Exchange (either On-Premises or Hosted) as a Destination, then a Proof of Concept should be run first. We do recommend using DeploymentPro in this scenario.

Exchange environments can have complex AutoDiscover settings, along with UPN and SMTP address mismatches, which can require troubleshooting and reconfiguration before DeploymentPro can be made to work against such environments.

DeploymentPro is included with the User Migration Bundle license. DeploymentPro cannot be purchased as a standalone service license, and it cannot be added to the single-use mailbox migration license. If you wish to remotely configure Outlook mail profiles using DeploymentPro after a migration, purchase the User Migration Bundle license.

The DeploymentPro Guide and DeploymentPro FAQ will guide you through the proof of concept, as well as any other DeploymentPro questions, while the DMA Installation and Introduction to DMA articles provide resources and guidance on DMA.

Prepare the Source Environment

Create Access Account

Ask the Hosted Exchange Provider to create an account for migration purposes (e.g., named MigrationWiz) and grant full access rights to each mailbox, by running this PowerShell script against the newly created account:
Get-Mailbox -ResultSize Unlimited | Add-MailboxPermission -AccessRights FullAccess -User MigrationWiz

Some Hosted Exchange providers allow this access to be granted via their web portal. In this case, you could log in to each mailbox via their portal and then grant the migration account (e.g., MigrationWiz) to have read/write access to each mailbox. This is laborious and time-consuming, so it is preferred that the Hosted Exchange provider run the PowerShell script above, particularly if you have a large number of users.

Some Hosted Exchange Providers will not grant this access. If that is the case, then you can request credentials from your end users during the migration. 

Request User Credentials

Create a project without admin credentials, and request credentials from users.

  1. Create a MigrationWiz mailbox migration project. When entering the Source information, do not click on the checkbox to enter admin credentials.
  2. Click on the green bar Bulk Add.
  3. Click on the checkbox I don't know the login name and password for the Source mailboxes.
  4. Click on the Upload bar.
  5. Click on the Choose File button, and select and upload your CSV file that contains the list of mailbox names.
  6. Click on the Save button.

When you submit the mailbox for migration, we will send an email with a secure link that allows the end user to provide their credentials directly to the system. The sequence of steps is as follows:

  1. You submit the item for migration.
  2. An email is sent to the email address configured with a secure link to provide the credentials.
  3. The end user clicks on the provided link, which opens a secure web page.
  4. The end user provides their credentials directly to our system.
  5. The credentials are verified.
  6. The item is immediately submitted for migration.

The status of the migration will remain as "Waiting For End User" until the end user provides their credentials to the system.

Optional - Large Projects

If this is a very large project, the best results will be achieved by setting the project to use impersonation at the Source. To enable this, the PowerShell script below needs to be run by your Hosted Exchange provider, if they are willing.
New-ManagementRoleAssignment -Role ApplicationImpersonation -User <admin_user_name>

The second part of this process is to set your MigrationWiz project Advanced Options to use impersonation at the Source. This step is included in the MigrationWiz section in this guide.

Prepare Mailboxes

  1. Test mailbox access
  2. Export mailboxes to CSV file(s).
    • Ask the Hosted Exchange provider to provide them. 
    • If the provider has an admin console that includes this capability, run their tool to export the user list (and, if necessary, the passwords) to the CSV file.
    • If you have admin credentials on the Hosted Exchange environment, you only need a list of the email addresses. You do not need the password for each mailbox being migrated (because MigrationWiz will use delegation and perform the migration based on the admin credentials).
    • If you do not have admin credentials on the Hosted Exchange environment (which is common), you must obtain all the email addresses and passwords for the users.
    • If the list of mailboxes and passwords from the Hosted Exchange provider is not available, request that the users send these to MigrationWiz as part of the migration process.

Prepare the Destination Environment

Create the Admin Account

  1. Create a user in Office 365
  2. Connect to Exchange Online by using remote PowerShell
  3. Type the following command, and then press Enter:
    Get-Mailbox -ResultSize unlimited -Filter {(RecipientTypeDetails -eq 'UserMailbox') -and (Alias -ne 'Admin')} | Add-MailboxPermission -User AdministratorAccount@mydomain.com -AccessRights fullaccess -InheritanceType all

After you perform these steps, the specified user will be able to access all user mailboxes in Office 365. The user will be able to view the contents of the mailboxes from either Outlook or Outlook Web App.

Set up Accounts in Microsoft 365

Set up accounts on Microsoft 365 and assign licenses. These can be created in several ways:

Prepare the Tenant to Receive Large Items
Microsoft has increased the size limits on migrated items. To customize this in the tenant, see the Item Size Limits documentation from Microsoft.

Modern Authentication Requirements

The steps listed in the Obtain Client and Tenant ID Settings for Mailbox and Exchange Online Migrations section of the Authentication Methods Migrations KB apply to both the source and 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.

Please review the documentation before preparing the destination.

Updated Mailbox Permission Steps to Use in Place of the Application Impersonation Role

Starting in May 2024, Microsoft announced that they will begin blocking the assignment of the Application Impersonation role in Exchange Online and that in February 2025, they will completely remove this role and its feature set from Exchange Online, for more information click here.

If you do not already have an admin account with the Application Impersonation role assigned, use the steps outlined in the following KB to add the necessary API permissions (to use in place of the Application Impersonation role) to the Modern Authentication app you are using for your O365 mailbox or archive mailbox endpoint.

Deploy DMA to Users

GPO is the recommended methodology because no end-user interaction is required. However, DMA may also be deployed via email, which requires users to manually install it on their computers.

Via GPO

Step 1: Download the DMA setup file from MSPComplete.

  1. In MSPComplete, click on All Customers from the navigation sidebar. 
  2. Click on the customer name for which you wish to deploy DMA.
  3. On the horizontal menu bar, click Users.
  4. Click Add Users, and then click Add Users via Device Management Agent
  5. On the Add Users via Device Management panel, click the Device Management setup file to download the DMA setup file to your local drive. Please note that this file should not be renamed or altered in any way or it could cause issues when DMA is installed. These instructions are more detailed than those listed in the Add Users via Device Management Agent panel. 

Step 2: Create a network share that is accessible to all of your customer’s computers and put the DMA setup file in the shared folder.

  1. Log on to the file server as an administrator.
  2. Click Start and search for Server Manager.
  3. Click Server Manager from the search results.
  4. Click File and Storage Services
  5. Click Shares
  6. Next to Shares, click Tasks
  7. Click New Share
  8. Continue through the New Share Wizard prompts until finished, then click Create
  9. Right-click on the new share in Server Manager, and click Open Share
  10. Put the DMA setup file in the share.

Write down the share's network path. This will be needed when creating the scheduled task.

Step 3: Create a Group Policy Object that forces the domain-joined computers in a security filter to execute the DMA setup file through a scheduled task.

  1. Log on to the Active Directory Domain Controller as an administrator.
  2. Click Start and search for Group Policy Management.
  3. Click Group Policy Management
  4. Right-click on the desired Active Directory domain, and then click Create a GPO in this domain, and link it here.
  5. Enter a name for the GPO, and then click OK. By default, the GPO will apply to all users and computers that successfully authenticate to the Active Directory domain.
    1. To narrow the scope of computers that install DMA, select Authenticated Users, and click Remove
    2. To confirm the removal, click OK.
  6. To add a new security filter, click Add.
    1. Type the name of the security group that the target computers are a member of and click Check names
    2. Click Ok.
  7. Right-click on the new GPO, and then click Edit
    1. In the console tree, under Computer Configuration, click PreferencesControl Panel > Scheduled Tasks.
    2. Right-click Scheduled Tasks, click on New, and then click on Immediate Task (At least Windows 7).
    3. Enter a name and a description for the Scheduled Task.
    4. Click Change User or Group
    5. Type "system" in the Object name text box.
    6. Click Check Names. Make sure that the system object name resolves to NT Authority\System.
    7. Under Security options, click Run whether a user is logged on or not and add a check next to Run with highest privileges.
    8. In the Configure for drop-down menu, select Windows 7, Windows Server 2008 R2
    9. Click the Actions tab
    10. Click on New.
    11. In the Action drop-down menu, select Start a program
    12. In the Programs/script text box, enter the network path for the DMA setup file. If you use the Browse button to find the location of the script, then it will add the path as c:\xxxx. This is incorrect since the script needs to include the UNC path and not the local path. Be sure to replace the c:\ format with the \\servername\sharename\ format.​
    13. If the customer's computers use a proxy, you must add a command line parameter into the Add arguments field to ensure that DMA is able to transmit data through the proxy. Read the How do I deploy the Device Management Agent on computers that use a proxy?​​ article for more information.​
    14. Click Ok.
    15. Click the Conditions
    16. Add a checkmark next to Start only if the following network connection is available, and then select Any connection.
    17. Click Ok
  • Close Group Policy Management Editor, and then close Group Policy Management.
  • The DMA setup file will execute on user computers at the next Group Policy refresh, typically every 90 minutes, with a random offset of 0 to 30 minutes.
Via Email

To deploy the BitTitan Device Management Agent (DMA) through email, you ask users to manually install the agent. We recommend installing DMA through a group policy object because it’s automated and non-intrusive.

  1. Click Customers on the navigation sidebar.
  2. Click the customer name for which you wish to deploy DMA.
  3. Click Users.
  4. Add a checkmark next to the user(s) that should receive the email.
  5. Click the Enable Device Management Through Email button.
  6. In the Enable Device Management via Email panel, enter your email address in the Reply-To Address field.
  7. Confirm that all of the users you chose are listed in the To field.
  8. To personalize the email message that the customer's users will receive, type your changes into the message body text box. If the customer's computers use a proxy, you must add instructions to run the DMA installer with command line parameters that ensure DMA can transmit data through the proxy.
  9. Click Send Agent Email.
    Important
    DO NOT
     change the name of the DMA setup file sent via email, or let users share the file. Each file is only for the user and machine it is sent to.
  10. The customer’s users will receive an email asking them to manually install the agent.​ The users and their computer information will start populating in MSPComplete under the customer’s context soon after the agent is installed and running.

Once DMA has been deployed to users, check the Users tab in MSPComplete. This will be populated with the user accounts that have DMA installed.

DeploymentPro Steps

  1. Launch DeploymentPro.
    1. Go to All Products > Device Management, click on DeploymentPro on the far left, and follow the prompts to launch.
    2. Select a customer from the list by clicking on the customer name. The status column will show Enabled when a customer account has had DMA deployed to users.
    3. Configure customer DeploymentPro module:
    4. Enter the Domain.
    5. Select the Destination endpoint.
    6. Checkmark the Auto-populate option. 
    7. In the Client Interface Configurations section, upload your company logo and add supporting text. We strongly recommend doing this because this is the logo and text that end users will see in a desktop pop-up when they are prompted to reconfigure their Outlook profiles. If you do not upload your logo, the default BitTitan logo will be included instead.
    8. Save and continue.
  2. Activate the DeploymentPro module for users by either selecting all users (by check-marking the box to the left of the Primary Email column heading) or selecting individual users (by check-marking the boxes to the left of the user email addresses).
  3. Click the Schedule Cutover.
  4. Schedule the profile cutover date.
  5. Set the date and time for the Outlook profile configuration to occur, and click the Schedule Cutover.
    1. The DeploymentPro module will install on user devices immediately and then run silently until this date.
    2. The profile cutover date should be set to a date and time that is shortly after the MX record cutover.
    3. On the profile cutover date, users will be guided through the reconfiguration of their Outlook profile.

MigrationWiz Steps

Create a Mailbox Migration Project

  1. Click the Go to My Projects button.
  2. Click the Create Project button.
  3. Click on the type of project that you wish to create. For this migration:
    • Mailbox: Mailbox projects are used to migrate the contents of the primary user mailbox from the previous environment to the new environment. Most mailbox migrations can migrate email, calendars, and contacts.

For mailbox migrations, use administrative credentials to access the mailboxes being migrated. In most migration scenarios, the admin account needs to have full access rights to the Source mailboxes. 

  1. Click Next Step.
  2. Enter a Project name and select a Customer.
  3. Click Next Step.
  4. Select or create a source endpoint.
  5. Select or create a destination endpoint.
  6. Click Save and Go to Summary.

Endpoints

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

Important

If you select an existing endpoint, keep in mind that the drop-down only shows ten endpoints. If you have more than ten, you may need to search.
Endpoint search is case and character-specific. For example, Cust0mer 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. 

Client Secret for Microsoft 365 Endpoints

For all Microsoft 365 Endpoints mailbox migrations (including archive migrations), MigrationWiz adds the Client Secret field, which is not always mandatory. It will depend on the permissions of the user account that performs the migration. Please review the following information before the creation of your M365 endpoints.

  • The client secret value is not mandatory if you use delegated permissions. Please leave the Client Secret field empty.

  • The client secret value is mandatory if you use the RBAC approach for application impersonation.

  • If you already have an admin account with the Impersonation role enabled (not using the RBAC approach) the client secret value is not mandatory. Please leave the Client Secret field empty.

Create a Source Endpoint

  1. Click New.
  2. Name endpoint.
  3. Select type Exchange Server 2003+.
  4. Enter the OWA URL.
  5. Provide credentials: Click the Provide Credentials radio button, and enter the admin account credentials for the account that was set up under the “Prepare the Destination Environment” section of this guide.
  6. Click Add.
  7. Click Next Step.

Create a Destination Endpoint

  1. Click New.
  2. Name endpoint.
  3. Select type Office 365.
  4. Provide credentials.
  5. Click Add.
  6. Complete the Application (client) ID, the Directory (tenant) ID, and the Client Secret fields.Destintation Settings.png

    Important

    Do not forget to complete the client ID, and the tenant ID fields, otherwise, you cannot save your project migration.

Once the information has been provided for both, the source and/or destination endpoint, and the customer selects Save and Go to Summary, MigrationWiz performs an endpoint validation check.

This validation tests the administrator credentials entered into the project and the Modern Authentication setup only. If there is an issue, the screen redirects to the endpoint and provides an error message or flyout that can be selected for more information regarding the error.

Common Errors when Configuring Your Endpoint

For more information, review the AADSTS700016, AADSTS90002, and ADDSTS50126 issues on the Common Errors Using Modern Authentication page.

Add Users

Add the user accounts that will be migrated to the project. MigrationWiz allows you to bulk import mailboxes into the system. Bulk Add uses a CSV containing the source and destination email addresses for the users to add the users to the project.

Use the Bulk Add option, and then import from the CSV file that you prepared when following the steps under the Prepare the Source section of this guide.

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.

Add the accounts (also referred to as "items") that will be migrated to the project.

If the list of mailboxes and passwords from the Hosted Exchange provider is not available, request that the users send these to MigrationWiz as part of the migration process.

Advanced Options

Recommended Options

Under Support/Support Options

  • If using impersonation, the value for Maximum concurrent migrations, under the Performance section, can be set to a very high value, e.g.,1000. There is no limit to this value if using impersonation.​
  • If not using impersonation, we recommend that you set the Maximum concurrent migrations value to a low number, such as 20.
  • If this is a very large project, the best results will be achieved by setting the project to use impersonation at the Source (as documented in the Prepare Source Environment section of this guide). However, many Hosted providers will not accommodate this request. If they do, checkmark the box for Use impersonation at the source. Exchange impersonation (not delegation) utilizes per-user throttling quotas, which allows for a very large number of users to be migrated concurrently.
  • Set to use impersonation at the Destination. Checkmark the Use impersonation at Destination box. 

Default Options for Microsoft 365 Endpoints

By default, some fields are view-only. In other words, you cannot edit or remove them from the support options page. To edit them, you need to edit the source or destination endpoint of your project.

Among these default options, you can find ModernAuthClientIdExport, ModernAuthTenantIdExport, ModernAuthClientSecretExport, ModernAuthClientIdImport, ModernAuthTenantIdImport, and ModernAuthClientSecretImport. 

The support options above are required when configuring your endpoint.

Important

Keep in mind that the ModernAuthClientSecretExport and the ModernAuthClientSecretImport support options are text-masked.

Warning

You cannot update the default Advanced Options, in case you try to modify or add new ones the following message arises.
Duplicate Support Option.png

Run Verify Credentials

  1. ​Sign in to your MigrationWiz account​.
  2. Open the Project containing items you wish to validate.
  3. Select the items you wish to validate.
  4. Click on the Start button in your dashboard.
  5. 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.

Run Migration

Pre-Stage Pass

  1. Select the users 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.

MX Record Cutover

Change over MX records on the DNS provider's portal.

Also, include the AutoDiscover (CName) setting.

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

Notify Users

Send an email to end users to let them know what to expect for their Outlook profile reconfiguration. Samples and screenshots can be found in our DeploymentPro documentation if you are utilizing that tool. 

Full (Delta) Pass

  1. Select the users.
  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.

Outlook Configuration

If not using DeploymentPro, then users must now create new Outlook profiles, set up their signatures again, and reattach any PST files that were attached to their previous profile.

Request Statistics

Click the pie chart icon in the MigrationWiz dashboard to receive an email containing all the project migration statistics.

 

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