Migration from hosted Exchange server to Office 365

Once you start the program, you will see the Dashboard tab. Click Create a new migration job link on the How to start card. Select the source server type: Exchange Server. The Create Exchange migration job wizard will open. Set the name of the job and select The program is installed outside the source Exchange server domain (the Migrate mailboxes using a CSV file containing a list of already matched source and target mailboxes checkbox will be selected automatically). Next, go to the Mailbox types step. Here, select if you want to migrate primary mailboxes, archive mailboxes or both.

Proceed to the Mailboxes step. If this is your first migration job, you will need to configure a connection to a hosted Exchange server. Click Add new source connection in the Source server drop-down meu and a wizard will open. You need to go through these steps:

• Server connection – in this step, provide your server’s FQDN or IP address. Options that are unavailable for this connection method, e.g. the Autodiscover feature, are greyed-out.
• Admin account – here, you need to enter the primary SMTP address and password of the admin account that will be used to access mailboxes on the source server. Remember that the admin account must be assigned the ApplicationImpersonation role to the mailboxes you want to migrate (as specified in Pre-migration activities - Step 2 above). 
• Configuration – this process configures your connection based on the settings provided in the previous steps. With the Check the impersonation settings button, you can check beforehand if the admin account is actually assigned the ApplicationImpersonation role for a given source user mailbox.

Click Finish to close the server connection wizard.

After successfully configuring the source connection, you will get back to the Mailboxes step of the migration job wizard. Now, set up a new target server connection by choosing Add new target connection from the Target server drop-down menu. A simple wizard will open:

• Application registration – decide how you want CodeTwo Office 365 Migration to be registered in the Entra ID (Azure AD) of your target Office 365 tenant: automatically by the program (an account with the Global Administrator or Privileged Role Administrator role will be required) or manually by yourself. If you select the second option, you will be asked to provide the application registration details in the next step.
• Application details – enter the necessary application information. Additionally, you need to enter an email address of any user from your target Office 365 tenant. 
• Configuration – this process registers CodeTwo Office 365 Migration in your Entra ID (if you have selected the Automatic registration option in the Application registration step) and configures the connection to the target Office 365 tenant.

After your connection is established, click Finish to go back to the Mailboxes step.

Click Import from CSV and select the CSV file containing a list of already matched source and target mailboxes. The Import matched mailboxes window opens. You now need to map the columns from your CSV file with headings (parameters) used by the program. If the data shown in Step 2 – Review your data is not displayed correctly, adjust the CSV file formatting options, such as fields delimiter or file encoding. Learn more

Click Import when done and continue with the migration job wizard configuration.

You can configure the following additional options:

• Scheduler - allows you to set the job to be automatically started in the desired time periods, so you do not have to control it manually.
• Time filter - is used to exclude items that are older or newer than a particular date.
• Folder filter - may completely exclude specific folders from the migration process.
• Advanced settings - this step lets you define how many mailboxes should be migrated at the same time and set the maximum size of items to be migrated.

Move on to the JOBS tab and click Start on the toolbar to begin the migration. Once you start the migration, all items from the source mailboxes will be migrated to their corresponding target mailboxes.

If you notice any missing items in the target mailboxes, restart the migration by using the Run delta migration option.

Once the migration is finished and you have noticed that some new items appeared in the migrated source mailbox, just restart the migration by using the Run delta migration option. Please keep in mind that this feature migrates only new items, not the modified ones. Delta migration can also be used to resolve issues with any items that failed to migrate on the first attempt.

You need to change your MX records to enable mail flow to the new server.  Additionally, you should also set up Autodiscover record to facilitate connecting migrated mailboxes with a mail client (e.g. Outlook). To change these DNS records manually, follow the steps below:

1. Log in to your Microsoft 365 admin center (Office 365 admin center).
2. Go to Settings > Domains, select your domain and click DNS Management.
3. Choose I’ll manage my own DNS records and click Next.
4. Select Exchange checkbox and click Next.
5. On this page, find the details regarding MX records and CNAME records (Autodiscover) that you need to use at your domain registrar. For specific instructions on how to configure DNS records in your domain registrar, visit this Microsoft page.
6. Once the DNS records have been configured, click Verify back in Office 365. Please note that it may take several hours for the changes to propagate.

If your Outlook has problems connecting to Office 365, you need to create a new Outlook profile for each user in your domain. You can do it using a GPO or Microsoft Intune.