IMAP to Office 365 Shared mailbox migration

Planning is one of the most important steps before you begin your IMAP to Office 365 Shared mailbox migration. Here is a brief checklist of points to consider before you migrate.

• Remove unused mailboxes, mail items and duplicate files from the source.
• Make an inventory of items before you make the move. These should include but are not limited to the following items.
  1. User accounts, email addresses and login credentials
  2. The source and target details, browser and operating systems used
  3. Network settings, DNS configurations, MX records, firewall settings
  4. Outlook settings and version you are using in your organization.
  5. Licensing plans on your current source server
  6. Active Directory configuration and other dependencies associated with it.
  7. List of data and permissions from the source server that you want to transfer.
• Determine the size of the data and number of mailboxes you want to migrate.
  1. Decide if you want to migrate everything at once (cutover migration) or plan to migrate your data in stages (staged migration).
  2. Based on the preceding factors, estimate the approximate time that may take for the migration.
• Create appropriate user mailboxes on Office 365 and assign licenses to them.
• Ensure you have enough network capacity and bandwidth to migrate.
• Consider the throttling and message size limits on Office 365.
• Communicate the migration plan and changes to your end users and stakeholders.
• Perform a test migration before you start the actual one.
• Start the actual migration, verify the endpoints and update the MX records.
• Check for correct mail flow and configure Outlook for all the users.
• Plan for decommissioning unused apps and their settings post migration

On source IMAP server:

• Ready with your IMAP server hostname, port number, email address, and password.
• To migrate multiple users, download the sample CSV file from the EdbMails application and update the details such as IMAP server hostname, port number, email address, and password for each user's mailbox you want to migrate.
• If you are connecting to Gmail, create an app password and use it instead of your regular password.

   See how to find your IMAP server host name.

On Office 365 server:

• Prepare your target Office 365 tenant. See tenant roadmap for Microsoft 365.
• Purchase a suitable Office 365 licensing plan. You can also sign up for a 30 day free trial and decide to go with a suitable one later. Compare Office 365 business plans and Compare Office 365 enterprise plans
• Before migrating from IMAP server to Office 365, ensure that you create mailboxes for your user. You can choose EdbMails to automatically create mailboxes on target servers. However, if you want to create the mailboxes manually, refer to the links below
  • Add users and assign licenses to Office 365 users
  • Add several users at the same time to Office 365
  • Assign Microsoft 365 licenses to user accounts
• If you plan to migrate to public folders and shared mailboxes on Office 365, ensure that you create and configure them on the target server.
  • Create Office 365 Public folder and assign mailbox user
  • Create Shared mailboxes on Office 365 and set the correct permission
• Ensure that you have a global admin account with a mailbox for Auto Registration of EdbMails application on your Entra ID (Azure Active Directory). However, you can use either a global admin account or any user account with full access rights in the Manual Registration method.
• If you have a custom email domain to which you want to receive emails after the migration, you must add and verify the domain on Office 365. Steps to add a custom domain to Office 365 and steps to add DNS records to connect your domain.
• Ensure that you meet the network and bandwidth requirements for the migration. See network and migration planning, performance factors and best practices for Office 365 migration.
• Configure Office 365 to send and receive large messages. Follow the steps to increase the message size on Office 365 to 150MB. See message size limits on Office 365 for more information.

• • Step 1: Download and install EdbMails software

    • Download and install EdbMails on any Windows computer.
    • Launch the application and click the ‘Login’ button by entering the email address and password or ‘Start Your Free Trial’ button.

       See the complete list of system requirements for IMAP to Office 365 migration.

      

    • Select the migration option as ‘IMAP migration’ (All IMAP clients, Gmail, G Suite & more…)

      

  • Step 2: Connect to the source IMAP server

    • If you want to connect to a single user account, select ‘Single User / Account Migration.’ Choose the appropriate IMAP Host name from the list or enter it manually. Next enter the email address and password. If you want to connect to a Gmail account, ensure to create the app password and use it instead of password.

      

    • To migrate multiple mailboxes, choose the option for 'Multiple (Bulk) Users/Accounts Migration.' Download the sample CSV file and populate it with necessary details, including mailbox names, passwords, host names, and port numbers. Once completed, upload the CSV file into EdbMails and verify the list of mailboxes to proceed with the migration process.

      

       Refer to the EdbMails detailed steps on connecting to single and multiple users during IMAP migration.

  • Step 3: Select source IMAP server mailboxes

    • Choose the desired mailboxes and folders from the left panel.
    • Then, click on ‘IMAP to Office 365’ to establish a connection with the target server.

        See tips to optimize IMAP migration to Exchange online

      

  • Step 4: Connect to target Office 365 server

    • Choose the preferred method for secure OAuth-based modern authentication. The default option, ‘Auto Registration,’ requires Global admin access. Alternatively, in the Manual Registration method, you can use either a Global admin account or any user account with full access rights.

      

    • Next, select the desired migration option and proceed with the login on the Microsoft sign-in page.

      

    • After logging in successfully, choose one of the options to load the mailboxes from the target Office 365 server. You can also load mailboxes using a CSV file.

      

  • Step 5: Map source and target mailboxes

    • Choose the required mailbox mapping option

      

    • EdbMails automatically creates mailboxes on your target Office 365 server and assigns the necessary licenses.

       Learn more about the automatic mailbox creation process on the target Office 365 server.

    • After successfully creating mailboxes on the target server, EdbMails automatically maps the mailboxes and folders between the source and target servers, which is particularly advantageous for large-scale migrations. Alternatively, you can manually map source folders and subfolders to specific target locations as needed.

      

       Click the ‘Folder and Item Filter’ button to customize the migration process. For instance, the date filter enables users to migrate items based on a specified date range, allowing them to selectively transfer only the emails and data received during that period.

      

       

  • Step 6: Start IMAP to Office 365 Shared mailbox migration

    • After mapping the mailboxes, designate a job name and initiate the migration process. To review the migration report, click the ‘View Log’ button, which provides a comprehensive report detailing the number of emails, folders, and mailbox items successfully migrated.

      

• Step 1: Update DNS records (MX record) to point to Office 365

  Update your MX records in your DNS to start receiving messages on Office 365. This switch ensures smooth email operation with your newly migrated server. Additionally, set up the Autodiscover record for the Outlook connectivity to the migrated mailboxes.

• Step 2: Create a new Outlook profile for users in the new domain

  Remove any previous instances of the email account you may have on Outlook to avoid conflicts with Office 365. Configure and recreate the Outlook profile for each user in your domain after you complete the migration.

 For common migration issues, check the knowledge base articles. For more information on EdbMails IMAP migration, visit the frequently asked questions section or contact our support team.