Introduction

This article will guide you through the steps for migrating mailboxes from Hosted and On-Premises Exchange servers (versions 2007 and later) to Microsoft 365.

 We recommend reading through the complete guide before starting the migration to understand the process, timeline, and prerequisites. You will see notes called out throughout the guide; pay attention to these, as they may provide information to avoid migration failure.

 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.

 App passwords are not supported for the Microsoft 365 endpoint. 

 We strongly recommend that you use HealthCheck for Microsoft 365 before beginning the migration to see if the end user hardware and software is compatible with Microsoft 365. HealthCheck for Microsoft 365 is a free utility. 

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.

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

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

Exchange questions and troubleshooting

Our Exchange Mailbox FAQ, Exchange 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.

DeploymentPro & DMA

BitTitan DeploymentPro is a module of Device Management and the Device Management Agent (DMA) that remotely configures Outlook email profiles after you perform a mailbox migration to Microsoft 365. 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. We do recommend using DeploymentPro in this scenario.

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.

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. 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

You must complete the following steps to prepare your Source environment for the migration.

1. Create and configure permissions
2. Confirm access
3. Test mailbox access
4. Disable throttling limits

Detailed instructions can be found in the accordions below.

Preparing the Destination

You must complete the following steps to prepare your Destination environment for the migration.

1. Configure authentication requirements for EWS
2. Create administrator account
3. Set up impersonation
4. Set up full access

Detailed instructions can be found in the accordions below.

 Create and License User Accounts

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

• Manually, one at a time. Read the Add users individually or in bulk to Office 365 article from Microsoft for more information.
• By bulk import, via CSV file. Read the Add several users at the same time to Office 365 article from Microsoft for more information.
• By PowerShell script. Read the Create user accounts with Office 365 PowerShell from Microsoft for more information.

Licensing

We recommend that you purchase the User Migration Bundle license for this migration scenario. 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.

1. 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.

Apply licenses

• 1. 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 if the project was not created under your account.
  2. On the left navigation pane, click Customers.
  3. Click the customer that employs the user to whom you want to apply a User Migration Bundle license.
  4. Click the Users tab at the top of the page.
  5. Check the box to the left of the email for the user(s) to whom you want to apply a license.
  6. Click the Apply User Migration Bundle License button at the top of the page. It is recommended that users be added to the Customer page with the vanity domain. Then have the User Migration Bundle Licenses applied, before editing to show the .onmicrosoft domain, if the .onmicrosoft domain will be used for the migration.
  7. If there is at least one unassigned User Migration Bundle license available for each selected user, click Confirm. Important: If there are no User Migration Bundle licenses currently available to be assigned and your role in the workgroup is Manager or higher, the form that appears provides all the necessary information and will walk you through the steps of purchasing User Migration Bundle licenses.

MigrationWiz Steps

Create a Mailbox Migration Project

1. Click Go To My Projects.
2. Click Create Project.
3. Select a Mailbox migration type. 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.
4. Click Next Step.
5. Enter a Project name and select a Customer.
6. Click Next Step.
7. Select a Source Endpoint from the Endpoint drop-down menu. If an Endpoint has not been created, click New and provide the requested information in the Endpoint creation flyout window.
8. Select a Destination Endpoint from the Endpoint drop-down menu. If an Endpoint has not been created, click New and provide the requested information in the Endpoint creation flyout window.
9. Click Save and Go to Summary.

Add Accounts (Items)

Add the accounts that will be migrated, 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. 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.
• Autodiscover Items: MigrationWiz detects the mailboxes directly at the Source using Autodiscover. For more information, refer to Adding & Managing Items for Migration.
• For mailbox migrations, this feature is only supported when the Source is Exchange 2007 or later.
• This feature is not supported for in-place archive migration projects, even if the Source is Exchange 2007 or later.
• 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.
1. Select the Project for which you want to perform the bulk import.
2. Click Add.
3. Click Bulk Add.
4. Follow the instructions on the page.

Set Advanced and Support Options

Advanced Options allow you to choose your notifications, filtering, maintenance, licensing, performance, and some configuration options.

Support Options are advanced configurations that make use of PowerShell or code blocks to provide extra options or resources for your migration.

The following options are the most valuable for this migration scenario:

Recommended Options

The following options are most valuable for Exchange to Microsoft 365 migration scenario:

• Set to use impersonation at the Source. Checkmark the Use impersonation at Source box. 
• Set to use impersonation at the Destination. Checkmark the Use impersonation at Destination box. 
• Set Maximum concurrent migrations. To be very safe, we recommend initially setting this to 5. This means that when all mailboxes are selected and the migration begins, only the first five (5) mailboxes in the list will be migrated (using parallel processing), and then when the first of the five (5) completes, the next in the list will begin migrating, and so on down the list, through to completion of all mailboxes. If the Source server has enough server resources, set this parameter based on the bandwidth guideline of three (3) mailboxes per 1Mbps of bandwidth. Therefore, for example, if there is a 10Mbps connection, we recommend that the maximum concurrent migrations parameter be set to 30.

Run Migration

The following sections will guide you through setting up and launching your migration. Each header is one step, with its component steps below. Follow these steps in order, and read the notes for important information about dependencies or best practices.

Run Verify Credentials

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

Notify Users

Send out the final notification that the migration is beginning. Include when the migration will start, expected duration, any usage instructions during migration, and any expected steps or notifications for the post-migration timeline.

If using DeploymentPro, refer to the sample email for some sample text and screen shots that can be included in this email.

Pre-Stage Pass

1. Select the users.
2. Click the Start button from the top, and select Pre-Stage Migration.
3. Under the Migration Scheduling section, from the drop-down list, select 90 days ago.
4. Click Start Migration. 

MX Record Cutover

Change over MX records on the DNS provider's portal. Also, include the AutoDiscover (CName) setting. There are several options for this, based on the size of your project.

Small Projects

Manually set forwards during a migration on a per-user basis, from the individual users' portal. This is only a valid option for a small number of users. Forwards are useful if you are migrating users in batches, and switching some users over to the new Destination before others. Forwards allow for mail coexistence, but not for calendar free/busy coexistence.

1. Sign in to your account.
2. Click Settings.
3. Locate the Forwarding and POP/IMAP tab.
4. Click Add a forwarding address.
5. Enter the email address to forward to.
6. A confirmation email will be sent to the forward mailbox.
7. Validate the confirmation by logging in to the forward mailbox.
8. Go back to your account.
9. Select the forward mode.

We recommend not saving a copy locally, because when you migrate the mailbox to the destination, you will end up with duplicates.

Small to Medium Projects:

Manually set forwards during a migration on a per-user basis, from the admin portal. Forwards are useful if you are migrating users in batches, and switching some users over to the new Destination before others. Forwards allow for mail coexistence, but not for calendar free/busy coexistence.

1. Sign into your control panel.
2. Click the Organization & users menu.
3. Click on the user you wish to provide coexistence for.
4. Scroll to the bottom of the User information section.
5. Click on the link Add another destination. A new row should have been added.
6. Enter the email address of the new mailbox to coexist with. This email address needs to be different than the email address in your source
7. Make sure both checkboxes are selected (they already are, by default). There is one in front of the row and another under the column called Change SMTP envelope.
8. Unselect the checkbox in front of the row.
9. Click Save Changes.

Large Projects  

If you are migrating in batches and coexistence is required, you will not be cutting over the MX records until your final batch of users has been migrated, and you must perform two extra steps:

1. Set up mail forwarding.
2. Set up mail routing on Microsoft 365. 

Forwards for Coexistence

If you are not cutting over an entire domain/organization at once by changing the MX records, you can perform a phased migration and set up coexistence by setting up forwards on the mailboxes you wish to migrate.

This can be done via one of the following methods.

Note: We do not recommend setting up Exchange email contacts and a DNS Internal Relay for this, since this will not allow for any Delta Migration passes to be made afterwards because the mailbox no longer exists.

By PowerShell:

Here is how to do this via PowerShell:

Forward email to internal recipient and DON'T save local copy.

PowerShell command syntax:

Set-Mailbox -Identity <Identity> -ForwardingAddress <Office 365 User Email Address> -DeliverToMailboxAndForward $False

• Example: Set-Mailbox -Identity John -ForwardingAddress Suzan@o365info.com -DeliverToMailboxAndForward $False
• Because you set DeliverToMailboxAndForward to false, a copy of the email will NOT be kept in the on-premises mailbox. When setting up forwards, make sure that you do NOT save a local copy before the forward. If you do save a local copy, then when you perform Delta passes, MigrationWiz will migrate the items that it previously hasn’t migrated (and watermarked). This will cause duplicates at your Destination.
• The email address specified on the 'ForwardingAddress' parameter should exist as a Mail Contact.

Through Exchange Management Console

The first step is to create the forwarding objects in your local Active Directory. These forwarding objects will be hidden from the address book, and will be used purely to forward mail for mailboxes that are migrated. Note that these objects are created but not used until you set the forwarding, so these steps can be done ahead of time.

1. Download our script to create forwarding objects to a computer that is joined to the domain.
2. Modify the script in a text editor (like Notepad) and change the forwarding domain in the top of the script to the temporary domain in the new environment, for example, company.onmicrosoft.com.
3. Run the script. You will know the script is complete when you see a confirmation.

The next step is to set up forwarding for mailboxes prior to migration. Before submitting a mailbox for migration, set the forward by performing the following:

1. Launch the Exchange Management Console from the Start Menu.
2. Expand the Recipient Configuration note from the navigation tree.
3. Click the Mailbox node from the navigation tree.
4. Right-click on the mailbox to set the forward for and click Properties.
5. Click the Mailbox Flow Settings tab.
6. Select Delivery Options and click Properties. Do not select the option "Deliver message to both forwarding address and mailbox". This is important to ensure that Delta passes do not cause duplicates. If you do save a local copy, then when you perform Delta passes, MigrationWiz will migrate the items that it previously hasn't migrated (and watermarked). This will cause duplicates on your Destination.
7. Click the checkbox Forward to, then click Browse.
8. Select the name of the user that contains the prefix (External Forward) in the display name. This is the forwarding object created previously. 
9. Click OK.
10. Click OK.

Setting up Mail Routing on Microsoft 365

For the setup, use PowerShell, because it is faster and easier to set up than working through the Microsoft 365 admin portal. If you need information about how to do this through the Microsoft 365 admin portal, contact Microsoft Support.

1. Connect to Exchange Online PowerShell.
2. Create the Distribution List (DL):
   New-DistributionGroup -Name "BtNotMigratedUsers"
3. Add All Users to this DL.
4. Create the Connector:
   $result = New-OutboundConnector -Name "CBRConnector" -ConnectorType OnPremises -SmartHosts "<fill smart host to source environment>" -UseMXRecord $false -IsTransportRuleScoped $true
   • -SmartHosts entry needs to be set to the URL or IP Address of the Source environment server.
   • On Exchange 2003, 2007, and 2010, this will be the address of the Transport server.
   • On Exchange 2013 and 2016, this will be the address of the Mailbox server, not the Transport server.
   • If the Source environment is Hosted, you would need to obtain this address from the Hosted Provider.
   • If the Source environment is G Suite, you would need to change the -SmartHosts entry to be the following: -SmartHosts “aspmx.l.google.com”
5. Create Rule:
   $result = New-TransportRule -Name "PilotInABoxRule" -SentToMemberOf "BtNotMigratedUsers" -RouteMessageOutboundConnector "CBRConnector"

When a user is fully migrated, remove the user from the DL, and they will receive their email in their own Microsoft 365 mailbox.

• There must be a mail-enabled contact on-premises for each user that has been migrated.
• Send email to end users to let them know what to expect for their Outlook profile reconfiguration. If using DeploymentPro, refer to the Sample email to send to users before their Outlook profile is reconfigured article for some sample text and screen shots that can be included in this email.

Run Full Pass Migration

1. Select the users – you may either select individual users, or select all users in a project by clicking the checkbox to the left of Source Email.
2. Click the Start button from the top.
3. Select Full Migration. If you want to delay your migration, then select the checkbox marked "Automatically start the migration at", and enter the date and time to have the migration start. To start a migration immediately, you do not need to select the scheduling option.
4. Click Start Migration. 

Run Retry Errors

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 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. Click the Go To My Projects button.
2. Select the project that contains the mailboxes that you want to retry.
3. Select the mailboxes that have migration errors.
4. Click the Start button.
5. Select Retry Errors from the menu.
6. 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.

Final Steps

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

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