This is the complete onboarding task flow for migrating mailboxes from Microsoft 365 to Hosted Exchange or On-Premises Exchange, version 2013+.

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.

Limitations

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.

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.

Below is a list of items that are and are not migrated using MigrationWiz on Microsoft 365 migrations. Please note that this list is updated frequently, so double-check it before any and all migrations.

Exchange Web Services (EWS) must be enabled for the mailboxes in the Exchange Online tenant and the Hosted/On-Premise Exchange environment for this migration type

Prepare the Source Environment

Modern Authentication Requirements

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. 

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 Users.
5. Click Continue.

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

Disable throttling against the admin account

Exchange Server has very low throttling policy limits. We recommend disabling the throttling limits during the migration. This is only relevant if throttling policies are enabled in the Exchange environment. If you are creating or applying a throttling policy on Exchange, you will need to use delegation for this endpoint.

There are two options for this process. Choose which one works for you, and then expand the relevant set of instructions below. 

Option 1

Disable throttling against only the migrating account (if not using impersonation). This way, the admin account can migrate at a faster rate because it is not subjected to any throttling.

Use this option if you are not using impersonation during the migration, but instead using delegation. If migrating using admin credentials, it is only necessary to disable throttling against the admin account, rather than all users. If migrating mailboxes using administrative credentials at the Source, but not using impersonation, we recommend disabling throttling limits on this administrative account in order to improve the speed of migration.

We recommend you Set Up an Exchange Administrator Account and disable policy enforcement for this account.

Option 2

Disable throttling against all user accounts (if migrating using an admin account and using impersonation). This way the admin account can migrate at a faster rate because it impersonates user accounts, which are not subjected to throttling.

If migrating mailboxes using administrative credentials at the Source, and using impersonation, disabling throttling limits on all mailboxes will improve the speed of migration, but it is a security risk. The throttling limits are working together to protect an Exchange server from being overwhelmed by accepting and delivering messages.

Read Message rate limits and throttling before you execute the scripts below.

Prepare the Destination Environment

Set up the user accounts

You can use the csv acquired in the previous step as an easy reference point for creating these accounts. 

Create Admin Account

Create an admin account for migration that has full access permissions to all mailboxes. Any user account that is a part of the domain administrator, schema administrator, or enterprise administrator groups will not have any administrative rights to mailboxes, no matter how many permissions are granted. A security default of Exchange Server is to explicitly deny any user that is a member of these groups. This is why we recommend creating a new user account specific for migration.

1. Open the Exchange Admin Console.
2. Click New and select User Mailbox.
3. Click New User.
4. Enter "MigrationWiz" as the Display name.
5. Enter "MigrationWiz" as the Name.
6. Enter "MigrationWiz" as the User logon name.
7. Enter the service account password. 
8. Select Save.

To grant the account access, perform the following steps while in the Exchange Server machine. The command needs to be applied each time a new mailbox is created, since permissions are set directly on each mailbox. The administrative account will not have access until the permissions are applied.

1. Open the Exchange Management Shell.
2. Enter the following command:
   Get-Mailbox -ResultSize Unlimited | Add-MailboxPermission -AccessRights FullAccess -User MigrationWiz. Change the -User account to match the name of the admin account that was set up for migration. This username is the Administrative Username that needs to be entered under project source or destination settings, within MigrationWiz, when checkmarking the box labeled: Use Administrative Login.

Optional: Large Messages

If you want to be able to migrate messages with attachments larger than 10MB, the following limits need to be increased:

Licensing

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 UMB license type.
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.

MigrationWiz Steps

Create a Mailbox Migration project

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

Mailbox Migration Settings: Every setting on the project is applied to all mailboxes associated with that project. For settings that are represented as checkboxes, only selected settings are applied to the project. Not selecting a checkbox does not disable a selected setting inherited from the project.

1. Click the Go to My Projects button.
2. Click the Create Project button.
3. Select Mailbox migration type.
4. Click Next Step.
5. Enter a Project name and select a Customer.
6. Click Next Step.

Endpoints

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, 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.

1. Select a Source Endpoint or create a new endpoint.
2. To create a new source endpoint:
1. Click New.
2. Name the endpoint.
3. Select type Office 365.
4. 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.
5. Click Add.
6. Click Next Step.
3. Select or create a new destination endpoint.
4. To create a new destination endpoint:
1. Click New.
2. Name the 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.
5. Click Next Step.
6. Click Save and Go to Summary.

Add Users

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.

Set the Project Advanced Options

Impersonation

Set to use impersonation at the Destination. Checkmark the Use impersonation at Destination box if you chose to use Impersonation instead of Delegation. If you chose to use Delegation, this box needs to remain unchecked.

For large projects only: If this is a large migration project, increase the value for Maximum concurrent migrations​, under the Performance section, e.g., 200. This can be set to a high number if impersonation is set to be used at the Source, and your Destination Exchange server has plenty of resources available.

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.

Begin 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. Uncheck the box named Automatic Replies (This option will be removed from the Pre-Stage pass at a later date)
5. Under the Migration Scheduling section, from the drop-down list, select 90 days ago.
6. Click Start Migration.

MX Record Cutover

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

Send email to end users to let them know what to expect for their Outlook profile reconfiguration. If using DeploymentPro, refer to Sample email to send to users before their Outlook profile is reconfigured for some sample text and screen shots that can be included in this email.

Full (Delta) pass

1. Select the users.
2. Click the Start button from the top.
3. Select Full Migration. IMPORTANT: It is recommended to only migrate Automatic Replies in the last migration pass for the user. 
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.

Post-Migration

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