On-Premises Exchange 2003 to Microsoft 365 Migration Guide

This article will guide you through the steps for migrating mailboxes from On-Premises Exchange 2003 servers to Microsoft 365. This task flow will not work for Exchange 2007+ or Hosted Exchange.

We strongly recommend that you use HealthCheck for Microsoft 365 to check ahead of time to see if end user hardware and software is compatible with Microsoft 365. HealthCheck for Microsoft 365 is a free utility. 

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

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.

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.

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 mis-matches, 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.

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. 

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

Prepare the Source Environment

Set up admin account

To create an administrator account (e.g., MigrationWiz), perform the follow steps when logged into the Exchange Server.

  1. Open the System Manager.
  2. Expand the Recipient Configuration node.
  3. Right-click on the Mailbox node.
  4. Click on New Mailbox.
  5. Click on Next.
  6. Click on Next.
  7. Enter "MigrationWiz" as the first name.
  8. Enter "MigrationWiz" as the user logon name, and optionally select a user principal name (UPN) domain.
  9. Enter a password and confirm the password.
  10. Click on Next.
  11. Click on Browse to select a Mailbox database.
  12. Click on Next.
  13. Click on New.
  14. Click on Finish.

To grant the account access, enter the following command:

  1. Get-Mailbox -ResultSize Unlimited | Add-MailboxPermission -AccessRights FullAccess -User MigrationWiz

The above 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.

In the above script, the username "MigrationWiz" should be replaced with the name of the administrative account that was set up, by following the earlier instructions in this article.

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.

Test mailbox access

  1. Browse to https://login.microsoftonline.com.
  2. Log in as admin email address.
  3. Enter the exact same password as specified in MigrationWiz.
  4. Enter the Admin
  5. Click on Users, then Active Users.
  6. Search for users entered in MigrationWiz to make sure the admin email address and the end user´s email address specified in MigrationWiz are not misspelled by searching for them.
  7. Make sure all users have licenses assigned to them. All mailboxes on the Source system are created as mail users in Microsoft 365. When you assign a license to the mail user, it will become a mailbox user. We need a mailbox at the Destination in order to be able to migrate data.
  8. If you are not using impersonation, make sure the admin account has a license assigned to it. This can even be a temporary trial license.

Configure the Exchange authentication method

To configure the Exchange authentication method:

  1. Open the Exchange System Manager.
  2. Expand the Servers node.
  3. Expand the server node.
  4. Expand the Protocols node.
  5. Expand the HTTP node.
  6. Expand the Exchange Virtual Server node.
  7. Right-click on the Exchange node and select Properties.
  8. Click on the Access tab.
  9. Click on the Authentication button.
  10. Make sure Basic Authentication is selected as the only authentication mode, and a single backslash (\) is specified for the Default domain.
  11. Click on OK.
  12. Click on OK.
  13. For the Public node, repeat Steps 7-12​.

Make sure that the settings are identical in IIS:

  1. Open the Internet Information Services (IIS) Manager.
  2. Expand your server.
  3. Expand the Web Sites node.
  4. Expand the Default Web Site node (or website node that contains your Exchange virtual directories).
  5. Right-click on Exchange in the navigation tree on the left, and select Properties.
  6. Click the Directory Security tab.
  7. Click the Edit button within Authentication and access control section.
  8. Make sure Basic Authentication is selected as the only authentication mode, and a single backslash (\) is specified for the Default domain.
  9. Click on OK.
  10. Click on OK.
  11. For the Public node, repeat Steps 5-10.

Make sure to back out any .config file so that you can easily go back to the previous state.

Increase MAPI named property limits

  1. Start the Registry Editor on the mailbox server.
  2. Locate the following registry key:
    • HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeIS\<ServerName>\<Private-GUID>
  3. Set the following DWORD values or create new values if they do not exist.
    • NonMAPI Named Props Quota == 00007fff
    • Named Props Quota == 00007fff

You may either wait approximately 30 minutes for these values to take effect automatically, or reboot the server to take effect immediately.

These instructions have also been documented on the Microsoft website.

Prepare the Destination Environment

Create the admin account

  1. Create a user in Microsoft 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 Microsoft 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

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

Prepare the tenant to send & receive large items

Increase Message Size Limits

This is a two-step process. The reason for this is that if the message size limits of Exchange are increased, the IIS limits will also have to be increased to allow increased payloads. There are other non-standard settings that can also cause size restrictions for the IIS or EWS connections, but we are unable to troubleshoot or identify specific environment restrictions outside of these settings.

To display current message size limits:

Get-TransportConfig | Format-List -Property MaxReceiveSize, MaxSendSize
Get-SendConnector | Format-List -Property Identity, MaxMessageSize
Get-ReceiveConnector | Format-List -Property Identity, MaxMessageSize
Get-MailBox | Format-List -Property PrimarySmtpAddress, MaxSendSize, MaxReceiveSize

To increase message size limits on the Exchange Server:

Set-TransportConfig -MaxReceiveSize 150MB -MaxSendSize 150MB
Get-SendConnector | Set-SendConnector -MaxMessageSize 150MB
Get-ReceiveConnector | Set-ReceiveConnector -MaxMessageSize 150MB
Get-Mailbox | Set-Mailbox -MaxSendSize 150MB -MaxReceiveSize 150MB

 

Increase IIS Limits to Allow Accepting Payloads

There are three limits that should be increased in IIS:

  • maxRequestLength
  • maxAllowedContentLength
  • maxReceivedMessageSize

Follow these steps to increase the Exchange message size limits on your client access server:

  1. Open Windows Explorer.
  2. Navigate to %ExchangeInstallPath%FrontEnd\HttpProxy\ews\
  3. Open the file Web.Config in a text editor, such as Notepad.
  4. Find the XML tag starting with for each change.
  5. Change the existing value to maxRequestLength="200000" -- this occurs in one place in the Web.Config file.
  6. Change the existing values to maxAllowedContentLength="200000000" -- this occurs one place in the Web.Config file.
  7. Change the existing values to maxReceivedMessageSize="200000000" -- this entry occurs up to 12 times. This needs to be changed for each Authentication method.
    For example:
    <httpsTransport maxReceivedMessageSize="200000000" authenticationScheme="Anonymous" maxBufferSize="81920" transferMode="Streamed" />
    <httpsTransport maxReceivedMessageSize="200000000" authenticationScheme="Basic" maxBufferSize="81920" transferMode="Streamed" />
    etc.
  8. If you are running IIS7 and Windows 2008, it may be necessary to increase WCF settings.
  9. Save the file.
  10. IIS Reset is not needed, web.config changes are picked up by the next connection.

Follow these steps to increase the Exchange message size limits on your mailbox server:

  1. Open Windows Explorer.
  2. Navigate to %ExchangeInstallPath%ClientAccess\exchweb\ews\
  3. Open the file Web.Config in a text editor, such as Notepad.
  4. Find the XML tag starting with for each change.
  5. Change the existing value to maxRequestLength="200000" -- this occurs in one place in the Web.Config file.
  6. Change the existing values to maxAllowedContentLength="200000000" -- this occurs one place in the Web.Config file.
  7. Change the existing values to maxReceivedMessageSize="200000000" -- this entry occurs up to 12 times. This needs to be changed for each Authentication method.
  8. If you are running IIS7 and Windows 2008, it may be necessary to increase WCF settings.
  9. Save the file.
  10. IIS Reset is not needed, web.config changes are picked up by the next connection.
Increase Maximum Accepted Content Length

You may increase the maximum accepted content length by following these directions:

  1. Open Windows Explorer.
  2. Navigate to C:\Program Files\Microsoft\Exchange Server\ClientAccess\exchweb\ews
  3. Open the file Web.Config in a text editor such as Notepad.
  4. Go to the end of the file.
  5. Insert or edit the following XML code before the </configuration> tag:

    <system.webServer>
    <security>
    <requestFiltering>
    <requestLimits maxAllowedContentLength="104857600" />
    </requestFiltering>
    </security>
    </system.webServer>

If XML code is already present in the Web.Config file, edit it to match what is shown above.

Sample Web.Config before changes:

<configuration>
<system.web>
...
...
</system.web>
</configuration>

Sample Web.Config after changes:

<configuration>
<system.web>
...
...
</system.web>
<system.webServer>
<security>
<requestFiltering>
<requestLimits maxAllowedContentLength="104857600" />
</requestFiltering>
</security>
</system.webServer>
</configuration>

 

Increase Maximum Received Message Size

If you are running IIS7 and Windows 2008, you may need to increase WCF settings:

  1. Open Windows Explorer.
  2. Navigate to C:\Program Files\Microsoft\Exchange Server\ClientAccess\exchweb\ews
  3. Open the file Web.Config in a text editor like Notepad.
  4. Find all XML tags starting with maxReceivedMessageSize=
  5. Change existing values to maxReceivedMessageSize="104857600"
  6. Save the file.
  7. Open a Command Prompt (cmd.exe).
  8. Type: cd %windir%\system32\inetsrv
  9. Type: appcmd.exe set config "Default Web Site/ews" -section:requestFiltering -requestLimits.maxAllowedContentLength:104857600
  10. Run: iisreset

 

MSPComplete Steps

Create Customer

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

Purchase licenses

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. For questions on licensing, visit MigrationWiz Licenses

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 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.

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.

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
  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 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. 
  2. Step 2: Create a network share that is accessible to all of your customer’s computers and put the DMA setup file in the share 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.
    11. Write down the share's network path. This will be needed when creating the scheduled task.
  3. 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.
  4. To narrow the scope of computers that install DMA, select Authenticated Users, and click Remove
    1. To confirm the removal, click Ok.
  5. 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.
  6. 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 and 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
  7. Close Group Policy Management Editor, and then close Group Policy Management.
  8. 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 is able to transmit data through the proxy.
  9. Click Send Agent Email.
  10. 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.
  11. The customer’s users will receive the 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 own logo, the default BitTitan logo will be included instead.
    8. Save and continue.
  2. Activate DeploymentPro module for users by either selecting all users (by check-marking the box to the left of the Primary Email column heading), or select 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 MX record cutover.
    3. On the profile cutover date, users will be guided through the reconfiguration of their Outlook profile.

HealthCheck for Microsoft 365 Steps

  1. Go all All Products Device Management, then click HealthCheck for Microsoft 365 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.
  3. Review results. If any computers have a red X on their row, you should review the detailed results by clicking on the pie chart in the far right-hand part of the row.
  4. Include upgrading action items and costs in your Statement of Work.
  5. Perform remediation steps.

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 mailboxes​. 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 a Source Endpoint or create a new endpoint.
  5. To create a new 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
  6. Select or create a new destination endpoint.
  7. To create a new destination 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
  8. Click Next Step
  9. Click Save and Go to Summary.

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.

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.

Set the Project Advanced Options

    • Set Maximum concurrent migrations. When Exchange 2003 is the Source server, it is very important that this number should be set to a low value, to ensure that the Source server does not run out of resources. 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.
    • Set to use impersonation at Destination. Check the Use impersonation at Destination box. 

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 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.

Notify users

Send 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, and 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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