Office 365 to SmarterMail Migration

Office 365 and SmarterMail use different mailbox, authentication, administration, and mail-flow models. The migration method should match the data in scope: an IMAP-based workflow is suitable for email-focused migration, while SmarterMail also provides its own Microsoft 365 mailbox-migration utility for supported mailbox data.

This page focuses specifically on the Office 365 → SmarterMail direction. For broader Microsoft 365 migration capabilities, see the Office 365 migration Tool.

Prepare the target SmarterMail domain and user accounts, choose the migration method that matches the data in scope, authenticate to Microsoft 365, map the source mailboxes to their SmarterMail targets, transfer the supported data, validate a pilot mailbox, complete any required final migration pass, and change production mail flow only after the destination is ready.

Can SmarterMail Migrate Directly from Microsoft 365?

Yes. SmarterMail includes a mailbox-migration utility that can connect to Microsoft 365 and import supported mailbox data. SmarterMail's current documentation describes a Microsoft 365 sign-in flow and lets the user choose which available items to migrate. The exact data types available depend on the source and migration method.

EdbMails provides a separate Office 365-to-IMAP workflow that can be useful when the project requires the mapping, filtering, bulk-processing, reporting, and repeat-migration controls supported by the current EdbMails workflow.

Office 365 to SmarterMail Migration Methods

Plan the Data Scope Before Migration

Define the data that actually needs to reach SmarterMail before choosing the migration route. Email, attachments, and mail folders fit an IMAP-based transfer. If the project also includes contacts, calendars, tasks, or notes, confirm that the selected SmarterMail or EdbMails workflow supports those data types before including them in the migration plan.

Microsoft 365 Groups, Teams, SharePoint, OneDrive, and Microsoft-specific retention/compliance settings are separate workloads and should not be assumed to move as part of an email migration.

Why Organizations Move from Microsoft 365 to SmarterMail

• Existing investment in a SmarterMail hosting environment.
• Preference for self-hosted or provider-managed email infrastructure.
• Different subscription, hosting, or administration requirements.
• Need for direct control over the mail server, domain, and mailbox quotas.
• A simpler email-focused environment when the broader Microsoft 365 collaboration stack is not required.

The choice should be based on the organization's hosting, administration, security, compliance, collaboration, and support requirements rather than assuming one platform is universally better.

Review the Microsoft 365 Features You Still Need

Moving mailbox data does not automatically reproduce Microsoft 365 services such as Teams, SharePoint, OneDrive, Microsoft 365 Groups, Exchange-specific mailbox controls, Microsoft retention/compliance features, or Entra ID identity/security policies. Account for those services separately before retiring the Microsoft 365 environment.

Office 365 Source Prerequisites

• Inventory the Office 365 mailboxes, sizes, folder counts, and large messages included in the project.
• Confirm the Microsoft 365 authentication method required by the selected migration workflow.
• Verify the source permissions required to access the mailboxes.
• Review MFA and Conditional Access requirements that may affect authentication.
• Keep the source mailboxes available until target validation and mail-flow cutover are complete.

Prepare the SmarterMail Target

• Create or verify the target SmarterMail domain.
• Create the target user mailboxes before mapping them from Office 365.
• Confirm each mailbox quota and the total storage available for the domain/server.
• Obtain the IMAP hostname, port, SSL/TLS requirements, username, and password from the SmarterMail administrator or hosting provider.
• Confirm that the SmarterMail server is reachable from the system running the migration.
• Check firewall rules, TLS certificates, and any hosting-provider connection restrictions.
• Test one target mailbox before beginning a bulk migration.

Port 993 with SSL/TLS is common for secure IMAP, but the actual SmarterMail hostname and port depend on the server or hosting-provider configuration. Do not assume that mail.yourdomain.com is the universal server name.

Mailbox Quota and Message-Size Planning

Compare each Office 365 mailbox with its SmarterMail target quota before migration. Also check attachment/message-size limits, total domain storage, server disk availability for self-hosted deployments, and any hosting-provider bandwidth or connection restrictions. Oversized messages or a full destination mailbox can cause items to be rejected even when the source mailbox is valid.

Migration Planning

Plan the migration as a controlled sequence: target preparation → pilot → initial transfer → validation → final/repeat migration when required → DNS/mail-flow cutover → final validation. For broader methodology, see the Office 365 migration guide.

Before the production run, use the Office 365 migration checklist to review authentication, capacity, permissions, communication, and validation tasks.

Folder and Mailbox Mapping

Review source-to-target mailbox mapping before starting the migration. Standard folders can have different names or special-use behavior between Office 365 and SmarterMail, so validate Inbox, Sent Items, Drafts, Deleted Items, Junk Email, Archive, custom folders, and nested folders.

Where automatic mailbox mapping is available, review the proposed matches rather than assuming they are correct. Use manual mapping when a source Office 365 mailbox must be directed to a different SmarterMail account.

Run a Pilot Before the Full Migration

1. Choose one representative Office 365 mailbox.
2. Create and verify its SmarterMail target account.
3. Connect both systems using the selected migration method.
4. Migrate a controlled set of folders and messages.
5. Check folder placement, message dates, and attachments.
6. Test representative large messages.
7. Review the migration logs/report.
8. Adjust mapping, filters, quotas, or target settings before the bulk migration.

1. Office 365 to SmarterMail Migration Using EdbMails

   • Step 1: Download and install EdbMails

     • Download and install EdbMails on the Windows computer used for the migration.
     • Launch the application and sign in or start the free trial.

       

   • Step 2: Select Office 365 to IMAP migration

     • Choose ‘Office 365 Migration’ from the main dashboard.

       

     • Select ‘Office 365 to IMAP migration’ and enter a job name or keep the default one.
     • Click ‘Next’ to continue.

       

   • Step 3: Connect to the source Office 365 server

     • Click ‘Add New Connection’ to create a new source connection, or use ‘Connect to Existing’ for a saved connection.

       

     • Choose the required connection option and click ‘Next’.
     • Select the login method and authenticate using Microsoft secure sign-in.

       

     • Load the required mailboxes and select the source mailboxes for migration.

       

   • Step 4: Connect to the target SmarterMail server

     • Select ‘Connect to IMAP’ for the SmarterMail email migration.
     • For a single mailbox, choose ‘Single User / Account Migration’ and enter the SmarterMail account credentials and IMAP connection details.

       

     • For bulk migration, choose ‘Multiple Users / Accounts Migration’.

       

     • Select ‘IMAP Migration CSV File’ to download the sample CSV.

       

     • Enter the required target account details in the CSV, including mailbox name, password, SmarterMail IMAP host, and port.

       

     • Load the updated CSV file and review the listed target accounts before continuing.

       

   • Step 5: Map Office 365 mailboxes to SmarterMail

     • Review the source-to-target mailbox mapping and correct any mismatches manually.
     • Apply the required migration filters and folder selections.

       

   • Step 6: Start and review the migration

     • Click ‘Start Migration’ to begin the transfer.
     • Monitor the migration job and review the available logs.
     • After the initial run, validate representative messages, folders, and attachments in SmarterMail.

       

     • If the selected workflow supports a repeat or incremental pass, run it before the final mail-flow cutover.

Can Microsoft 365 and SmarterMail Run Together During Migration?

For staged migrations, organizations may temporarily operate Microsoft 365 and SmarterMail for different users in the same domain through a controlled mail-routing design. SmarterMail documents Split Domain Routing (SDR) for this type of coexistence. The exact DNS, connector, relay, and routing configuration depends on the environment and should be designed before the production transition.

Post-Migration Validation

• Check Inbox, Sent, Drafts, Deleted, Junk, Archive, custom folders, and nested folders.
• Compare representative messages, attachments, dates, and folder placement with the source.
• Review migration logs for completed, skipped, failed, or unmapped items.
• Confirm users can sign in to SmarterMail and access the expected mailbox data.
• Confirm mailbox quota and available capacity after the transfer.
• Test IMAP and SMTP/client access where those protocols are part of the production design.

DNS and MX Cutover

For a domain moving its production email service from Microsoft 365 to SmarterMail, MX and related DNS changes belong at the end of the migration sequence—not at the beginning.

1. Complete the initial migration.
2. Validate the SmarterMail target.
3. Run the required final/repeat migration pass.
4. Confirm SmarterMail inbound and outbound configuration.
5. Update MX and other required DNS records according to the target mail-flow design.
6. Validate inbound delivery, outbound delivery, SPF, DKIM, and DMARC after cutover.

Common Office 365 to SmarterMail Migration Problems

• Microsoft 365 authentication fails: Review the selected authentication method, required permissions, MFA, and Conditional Access.
• SmarterMail IMAP authentication fails: Verify the target username/password and whether IMAP access is enabled for the account.
• Connection fails: Check the SmarterMail hostname, port, SSL/TLS requirement, certificate, firewall, and network reachability.
• Target mailbox is missing: Provision the SmarterMail account before mapping and migration.
• Mailbox quota is exceeded: Increase the target quota or reduce the migration scope before retrying rejected items.
• Folders appear differently: Review special-folder names and source-to-target folder mapping.
• Large messages fail: Compare source and destination message-size limits and handle oversized items separately where required.
• Migration is slower than expected: Review network conditions, target server performance, Microsoft service limits, and connection concurrency.

Plan the SmarterMail Migration Around the Target Environment

An Office 365 to SmarterMail migration should be planned around the data being moved, the target mailbox configuration, authentication, folder mapping, quota/capacity, and final mail-flow cutover. Test a representative mailbox first, validate the result, and use a staged or repeat-migration approach when appropriate for the selected workflow.

---

Additional Resources:

• Office 365 to IMAP Migration Guide
• Office 365 to IceWarp Migration
• Office 365 to cPanel Migration
• Automatic Mailbox Mapping