Exchange 2016 to Office 365 migration

1. Office 365 is a cloud-based service that is managed by Microsoft. You don't need to worry about maintaining your own hardware or dealing with software issues.
2. With Office 365, you get desktop Office apps such as SharePoint online and OneDrive storage. You can easily add or remove users as needed, which makes it easy to scale your email system up or down to meet your changing needs.
3. Exchange online is a part of the Office 365 suite. However, you can also purchase a standalone Exchange online plan.
4. Office 365 is a subscription-based service, where you can pay for it on a monthly or annual basis, rather than having to make a large upfront investment in hardware and software.
5. Office 365 includes different plans for business and enterprise users. Compare the Microsoft 365 plans based on your requirements.

In this Exchange 2016 to Office 365 migration guide, we describe the prerequisites, best practices, actual migration operation and the post migration tasks.

What is the best way to migrate Exchange server 2016 to Office 365?

EdbMails for Exchange mailbox migration is the best tool for migrating Exchange mailboxes from 2016 to Office 365. Not only does it offer advanced features like incremental migration and automatic throttling management, but it also guarantees data consistency and integrity during the transfer operation.

With EdbMails, you can easily migrate a variety of items including mailboxes, folders, contacts, calendars, appointments, and more. In addition, its user-friendly interface enables a seamless migration without any data loss or downtime.

1. Exchange 2016 to Office 365 Migration Checklist

   Before you migrate from Exchange 2016 to Office 365 you must carefully plan the approach based on your current environment and migration requirements. Following is a checklist of items to identify and prepare your environments.

   1. Plan ahead: Get familiar with Microsoft 365 and learn how it is different compared to the on-premises environment.
      • Make sure to allocate enough time and resources for the migration.
      • Take a complete backup of Exchange 2016 mailboxes.
      • Identify the type of your current migration environment (Hybrid or non-Hybrid) and determine whether you want to move everything at once or in stages.
   2. Prepare your source environment: Before you begin the migration, ensure that your Exchange 2016 environment has the latest Exchange 2016 cumulative update and is properly configured. This may include tasks such as setting impersonation rights, checking your internet connection speed, network configuration and firewall rules.
   3. Test the migration process: It is highly recommended to perform a test migration before attempting to migrate your entire Exchange 2016 environment to Office 365. This can help identify any issues or problems that may arise during the migration and allow you to address them in time.
   4. Monitor the migration: After the migration operation, it's important to check the status of mailboxes, verify that all data has been migrated, and troubleshoot any issues that may arise.
   5. Plan for post-migration tasks: There are a number of post-migration tasks that need to be completed, including updating user profiles, training your end users, configuring client access, and decommissioning the Exchange 2016 environment. Make sure to allocate enough time and resources for these tasks.

2. Exchange 2016 to Office 365 Migration Prerequisites

   • Step 1: Decide on the Exchange to Office 365 migration approach

     The first step is to plan how you want to migrate to Office 365 from Exchange 2016. The following migration paths are available depending on your source and target environment.

     Current environment and migration requirement	Ideal migration approach	Migration flow
     You are looking to migrate all of your email, calendar, and contacts from an Exchange Server 2016 to Exchange Online in a single operation	Exchange cutover migration	With this method, you can migrate all of your email data at once to Office 365 and is suited for a large number of mailboxes.
     You prefer to move all of your mailboxes from Exchange Server 2016 in smaller increments or during the weekends.	Staged Exchange migration	In this approach, you migrate your mailboxes and mail data in stages, starting with the most recent data and then proceeding to the rest.
     You prefer to switch to Office 365 gradually rather than moving all at once due to certain on-premises requirements.	Hybrid migration	With this method, you can migrate from Exchange 2016 to a hybrid deployment consisting of both Exchange and Office 365.
     You prefer to keep on-premises Exchange due to legal requirements	Exchange to Exchange migration	Exchange migration 2016 to 2019

      Use the Microsoft 365 mail migration advisor to determine which migration method is best for you.

   • Step 2: Check the network and bandwidth requirements

     Estimate the bandwidth requirements to migrate to Office 365 and that the network settings allow you to transfer the data. See networking roadmap for Microsoft 365 which explains how to plan and deploy your network.

     1. Network connectivity
        • Ensure you have a stable and reliable internet connection at both the source and destination locations.
        • You should ensure that your network is configured correctly to allow communication with the Office 365 servers.
        • Open the necessary ports and allow traffic to and from the Office 365 servers.
        • If you have a firewall or proxy server in place, configure these to allow communication with the Office 365 servers. Consult with your network administrator or the vendor of your firewall or proxy server for specific instructions.
     2. Test your existing network
        • With tools like Microsoft Remote Connectivity Analyzer and Microsoft 365 network connectivity test tool, you can test your existing network.
     3. Bandwidth
        • The actual bandwidth required depends on the size of your mailboxes and the amount of data you are migrating. For example, if you have a large number of large attachments or folders, you may need more bandwidth.
        • As a general rule, it is recommended to allow the bandwidth 1.5 times the size of your mailbox data.
        • It's also important to consider the available bandwidth at the source and destination locations.

      See best practices for network planning and improving migration performance.

     Note: If you have already configured your Office 365 tenant, you can directly skip to Step 6 in this section.

   • Step 3: Choose a suitable Microsoft 365 license plan for your requirements

     Microsoft 365 is available as a cloud-based subscription service or as a one-time purchase of a perpetual license. Office 365 has business and enterprise plans, each suited to different user requirements. Compare Office 365 business plans and compare Office 365 enterprise plans. You can choose an Office 365 licensing plan specific to your needs or sign up for a 30 day free trial and decide to go with a suitable one later.

   • Step 4: Set up your target Office 365 tenant for the migration
     1. Plan for your tenant implementation and deploy your tenant. See tenant roadmap for Microsoft 365.
     2. Understand the subscriptions, licenses, Azure AD tenants and how to use third-party SSL certificates.
     3. Create user accounts: Create user accounts for all users who will be using Office 365 through the Microsoft 365 admin center.
     4. Configure security and compliance: Configure the required settings to ensure that your data is secure and compliant with relevant regulations. Set up data loss prevention policies, configure multi-factor authentication, and set up data retention policies.
     5. Set up your Office 365 environment: Configure any additional services you will be using, such as SharePoint, OneDrive and Teams.
     6. If you plan to install Office apps on your computer, see system requirements for Microsoft 365 and Office configuration support matrix. Because Office 365 is a cloud based solution, it is also important to learn where your Microsoft 365 customer data is stored.
   • Step 5: Add and verify the custom domain on Office 365

     If you have a custom email domain from your hosting provider to which you want to migrate and receive emails, you must add and verify the domain on Office 365. This will enable you to use your own domain name (such as example.com) for your email addresses and other Office 365 services.

     To set up your custom domain, follow these steps:

     1. Verify that you own the domain by adding a TXT record to your DNS configuration.
     2. Add a new domain to your Office 365 tenant. You can use an existing domain that you own or purchase a new one. The domain is used to access your Office 365 services.
     3. Update your DNS records to point to Office 365. This step is required to ensure that your email is delivered to the correct mailbox.
   • Step 6: Create mailboxes and mail-enabled Public folders

     Before you migrate to Office 365, ensure that you create mailboxes for your users in your organization and assign suitable licenses to them. If you need to create multiple user accounts at once, you can use the 'Bulk add users' option to create user accounts in bulk using a CSV file.

     1. Add users and assign licenses to Office 365 users
     2. Add several users at the same time to Office 365
     3. Assign Microsoft 365 licenses to user accounts

     If you want to migrate Public folders from Exchange 2016, ensure that you create and configure Public folders and make them mail enabled on Office 365.

     1. Create Office 365 Public folder and assign mailbox user
     2. Enable In-Place Archive mailboxes in Office 365
   • Step 7: Set the impersonation role to the admin user on the source

     Ensure that you set the following permissions to the admin account on the source and target server and that the mailboxes you migrate are not hidden from the address lists.

     1. On the source
        1. ApplicationImpersonation
        2. View-Only Configuration - Run the cmdlet New-ManagementRoleAssignment using the Exchange Management Shell to assign the View-Only Configuration role to the admin.
     2. On the target
        1. ApplicationImpersonation

     Setting impersonation rights in Office 365 is a simple process that can be done quickly and easily using the Admin Center. Assign the Organization Management role group to the admin user in Exchange online. It is an elevated permission that is required to migrate Public folders.

   • Step 8: Verify the mailbox of the admin account

     Check to see if the admin account that has been assigned management roles has a valid and non-hidden mailbox on the Exchange 2016 server. See how to configure user mailbox properties for the users from the Exchange admin center (EAC).

   • Step 9: Configure Office 365 to send and receive large messages

      Follow the steps to increase the message size on Office 365 to 150MB.

3. Exchange 2016 to Office 365 Migration using EdbMails

   The following methods can help you migrate mailboxes from Exchange 2016 to Office 365 with EdbMails migration tool.

   1. Exchange 2016 to Office 365 with the cutover method
   2. Hybrid migration Exchange 2016 to Office 365
   3. Migrate Exchange 2016 to Exchange online with EDB file
   4. Exchange 2016 to 365 migration using PST files

   Method 1: Cutover migration Exchange 2016 to Office 365

   The cutover migration enables you to completely migrate all your mailboxes and emails from the source to the target.

   • Download EdbMails and install the application on any computer that is connected to the source and target environment. You can also perform the migration operation by installing EdbMails on a Windows 11, 10, 8, or 7 computer.
   • Launch the application and click 'Login' or 'Start Your Free Trial'.

      See a detailed list of EdbMails system requirements for Exchange migration.

     

   • Step 1: Select the Live Exchange migration option in EdbMails

     Select the migration technique as Live Exchange migration in the selection screen.

     

     Note: If the Standard folders (such as Inbox, Calendar, Contacts) on your source Exchange server mailboxes are initialized with a different language, follow the details to migrate these folders to the respective system folders on the target (destination) server.

     For Instance: If your source Inbox folder is named 'Boîte de réception,' which is in French, and you migrate it directly to the target server, it will not be mapped to the target folder with the English name 'Inbox,' by default. To map the source folder with the French name to the right target folder, ensure that the regional settings on Exchange and Office 365 are the same.

      Steps to change the language and regional settings on Exchange and Office 365

   • Step 2: Set up connection with Exchange 2016 source server

     In the Connect to Exchange server (Source) window, select the 'Connect using Global Admin User'. You can also connect to Specific User, Hosted Exchange Server and load the mailboxes using a CSV file. See the different Exchange server connection methods supported by EdbMails.

     You can also load the mailboxes using a CSV file. See instructions on how to use the different Exchange server connection methods supported by EdbMails.

      With EdbMails, you can migrate mailboxes, public folders, and perform In-Place Archive to Office 365 migration

     

   • Step 3: Select the mailboxes and connect to Office 365 server
     • Select the mailboxes and folders from the Exchange that you want to migrate to Office 365.

        Tip: If this is the first time you’re migrating with EdbMails, the migration is a full migration. On subsequent migrations from the same source to the target, the migration is incremental.

     • Click 'Migrate to Office 365' to setup the connection with the target server

       

        Tip: EdbMails provides the following additional options to help you filter selected emails and mailbox items.

       1. Additional Include and Exclude Filter Options
       2. Filter emails by Date: Migrate to Office 365 by applying the Date filter
       3. Filter emails by Size: Exclude emails from migration larger than a specified size.
       4. Filter emails by domain: You can also filter emails by the sender address or the email domain.
   • Step 4: Log in to the target Office 365 tenant as Global Admin

     EdbMails supports both modern and classic authentication. Connect to Office 365 server by selecting Auto or Manual registration for modern authentication and the connection method as Mailboxes, Public folder or Archive Mailbox.

     EdbMails is a highly secure application and uses TLS encryption along with OAuth 2.0 authentication for login. It does not store your user credentials.

     

      Tip: The mailbox mapping activity in EdbMails can automatically match and map the mailboxes, folders between the Exchange server and Office 365. This feature saves time when you have a large number of mailboxes to map and migrate.

     

   • Step 5: Start the migration to Office 365 from Exchange 2016

     Start and monitor the migration operation after you complete the mailbox mapping. Finally, verify the count of migrated emails, folders and mailbox items with the EdbMails text-based log report. You can pause, resume or stop the migration anytime without data loss.

     

   Method 2: Exchange 2016 to Office 365 Hybrid migration

   In a Hybrid scenario, the Exchange and Office 365 mailboxes coexist in the same Active Directory (AD) environment. This migration method can be a good option if you want to gradually move to Office 365 or if you have specific on-premises applications that you need to keep running. EdbMails simplifies Hybrid migrations and enables you to directly migrate mailboxes from on-premises Exchange 2016 to Office 365 within or to the Hybrid environment.

    Make yourself familiar with the Exchange server Hybrid deployment and learn about the Hybrid deployment components. Consider the following points and ensure that you have the required bandwidth for the migration.

   • Ensure that you meet the Hybrid migration prerequisites
   • Install the latest version of the Exchange Server 2016 cumulative update on your on-premises servers.
   • Set up Office 365 and install Exchange 2019 in the target environment.
   • Install and use the Azure AD Connect tool in the target on-premises environment to set up the hybrid deployment. The Azure AD Connect enables you to set up a connection between your on-premises Exchange Server environment and Office 365.
   • Update any Edge Transport servers to the latest CU.
   • Register any custom domains you want to use in the Hybrid with Office 365.

   After you have completed the necessary prerequisites, use the Hybrid Configuration Wizard (HCW) to configure the hybrid deployment.

   Steps to migrate Exchange 2016 to Office 365 Hybrid

   Here’s is a general overview on the Exchange 2016 Hybrid migration

   1. Plan your Hybrid migration strategy
   2. Prepare your on-premises Exchange environment
   3. Set up a hybrid connection with the target
   4. Migrate your mailboxes with EdbMails
   5. Test and validate the migration
   6. Clean up your on-premises Exchange environment

   After you deploy the Hybrid environment, you can use EdbMails to perform the Exchange hybrid migration to Office 365. You can connect to the source and destination servers and directly move your mailboxes.

   For example, in the EdbMails connection window:

   • Choose the source as Exchange 2016 and target as Office 365, for Office 365 migration
   • Choose the source as Exchange 2016 and target as Exchange 2019, for on-premise Exchange migration.

   Method 3: Exchange 2016 to Exchange online migration with EDB file

   If you have an EDB file from Exchange Server 2016, you can use EdbMails to migrate mailboxes from the EDB to Office 365. This method is useful if your Exchange server is unavailable or if you want to repair and migrate a corrupted EDB file without using PowerShell cmdlets.

   • Step 1: Select the EDB to Office 365 migration option in EdbMails

     Install EdbMails and select the migration technique as 'EDB to Office 365, EDB to Exchange, EDB Public folder'.

     

   • Step 2: Add the Exchange 2016 offline EDB file for migration

     EdbMails can repair and fix dirty shutdown errors of an Exchange database and restore deleted mail items from the EDB file. Click 'Browse for EDB' and select the file from your computer that contains the mailboxes to migrate.

     

   • Step 3: Select the mailboxes and click Migrate to Office 365

     After the repair operation, you can preview emails, contacts, folders, calendars, tasks. Select the desired folders, mail items, and mailboxes and choose the Office 365 migration option as shown.

     

     In the Connect to Office 365 window, select Auto Registration. Choose the mailbox migration method and map the folders and mailboxes between the source and target.

     

   • Step 4: Migrate the Exchange 2016 mailboxes to Office 365

     Finally, start the mailbox migration from EDB to Office 365 and use the EdbMails log report to verify the number of migrated items, folders, and emails. You can also pause and resume the migration at any time in the application.

   Method 4: Exchange 2016 migration to Office 365 with PST files

   If you have mailboxes exported as PST files from Exchange server 2016, EdbMails can also assist you in migrating your mailbox data to Office 365. Download and run EdbMails if it hasn't already been installed on your system. The following steps outline how to migrate PST files from Exchange to Office 365.

   • Step 1: Select the migration method as Office 365 migration

     On the EdbMails migration selection window, select the migration method as 'Office 365 migration (Tenant to tenant migration & more…)'.

     

   • Step 2: Click ‘Migrate PST to Office 365’ and add the PST files

     To add the PST files, close the Connect to Office 365 (Source) connection window and select the migration option as shown. Click 'Add File(s)' and select multiple PST files from your computer.

     

   • Step 3: Log in to target Office 365 tenant as Global Admin User

     EdbMails supports both modern and classic authentication. Connect to the target server by selecting Auto or Manual registration for modern authentication and the connection method as Mailboxes, Public folder or Archive Mailbox.

      Connect to Office 365 server using secure modern authentication

   • Step 4: Map and migrate mailboxes to Office 365 from Exchange 2016

     The mapping activity in EdbMails can automatically match and map the mailboxes and folders from the PST file to Office 365. This activity saves time when you’re migrating a large number of mailboxes. After you complete the migration, verify the count of the migrated items, folders and mailboxes.

4. Post Migration Tasks

   • Step 1: Verify that all mailboxes have been migrated successfully

     It is important to verify that all mailboxes have been transferred to Office 365 and that all data has been migrated correctly. Ask your users to log in to their accounts and check if they have all their emails, contacts, calendars. It is also a good practice to change the passwords.

   • Step 2: Update the MX records to point to Office 365

     If you haven’t done this previously, update the DNS records known as MX records to enable and receive emails on Office 365. In addition, configure the Autodiscover recordto allow Outlook to connect to the migrated mailboxes.

   • Step 3: Notify and train your users to be familiar with Office 365

     After the migration, you should notify your users so that they can start using Office 365. You may also want to provide them with suitable training or documentation to help them get started with the new email system.

   • Step 4: Test email connectivity and perform a mailbox backup

     It is important to test the email connectivity after the migration to ensure that you are able to send and receive emails correctly. Take a complete Office 365 mailbox backup to ensure that you have a copy in case of any unexpected issues.

   • Step 5: Create a new Outlook profile for users in the new domain

     Ensure you have the latest version of Outlook installed to avoid compatibility issues. Configure the Outlook profile for each user in your domain if Outlook has problems connecting to Office 365 mailboxes.

   • Step 6: Decommission and uninstall Exchange server 2016

     If you have migrated from an on-premises Exchange server, you must decommission the server and remove any unnecessary components. Wait for a few days and test if everything is working as expected. Finally, uninstall and decommission Exchange server 2016.

     1. Remove the server from any database availability groups (DAGs) it is a member of.
     2. Remove any send connectors, receive connectors, and OAB (offline address book) generation servers that are configured on the server.
     3. Remove the server from the organization by running the Remove-ExchangeServer cmdlet in the Exchange Management Shell.
     4. Uninstall Exchange 2016 from your computer
        1. Open the Control Panel and navigate to Programs and Features.
        2. Select Microsoft Exchange Server 2016 and click Uninstall.
        3. Follow the prompts to uninstall Exchange from the server.
     5. Remove the server from Active Directory by decommissioning it.
        1. Open the Active Directory Users and Computers console.
        2. Right-click the server object and select Delete.

      See the list of post migration tasks to complete after you finish the Office 365 migration.

Exchange migration troubleshooting

 See Exchange migration troubleshooting guide for possible solutions related to migration errors.