Stellar Migrator for Exchange Review: Migrating from Exchange Server to Microsoft 365

Introduction

Migrating from Microsoft Exchange Server to Microsoft 365 requires careful planning to ensure that emails, calendars, contacts, attachments, and other business-critical mailbox data are transferred with minimal disruption. For IT administrators, even a small migration error can result in missing data, user downtime, or additional support requirements.

Stellar Migrator for Exchange is designed to simplify this process by providing a guided workflow for migrating mailboxes from an on-premises Exchange Server to Microsoft 365. It brings source and destination connections, mailbox mapping, migration scheduling, progress monitoring, and reporting into a single interface.

In this review, we explore the software’s installation, configuration, and migration workflow, along with its key features, advantages, limitations, and overall suitability for IT administrators, Microsoft 365 consultants, and managed service providers (MSPs).

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How to Use Stellar Migrator for Exchange: Step-by-Step Guide

Step 1: Download and Install the Software

Download the latest trial version of Stellar Migrator for Exchange from the official product page.

Install the application on a supported Windows and launch it.

The trial edition allows you to migrate up to two mailboxes with their mailbox data at no cost, providing an opportunity to evaluate the workflow before purchasing a license.

Step 2: Select the Source and Destination Servers

After launching the software, select the source and destination server types.

For this demonstration, I selected:

• Source: Exchange Server
• Destination: Microsoft 365

This configuration sets up the migration project for transferring mailbox data from an on-premises Exchange environment to Microsoft 365.

Enter a job name and create a new migration project. Depending on the available options and migration requirements, select the relevant mailbox or folder types for the job, such as primary mailboxes, archive mailboxes, or public folders.

Selecting the appropriate data scope helps keep the migration aligned with organizational requirements.

Step 3: Connect to the Source Exchange Server

The next step is to establish a connection with the source Exchange Server.

The software provides two connection approaches:

• Auto-discovery: Enable the auto-discover option and enter the required email address and password.
• Manual configuration: Disable auto-discovery and enter the Exchange Server IP address or fully qualified domain name (FQDN), along with the required credentials.

After entering the connection details, click Validate to verify the connection and credentials. Once validation is complete, proceed to the next step.

Step 4: Discover and Select Source Mailboxes

Once the source connection is established, Stellar Migrator for Exchange displays the available mailboxes on the Exchange Server.

Review the list to confirm that the required mailboxes have been detected.

For migrations involving more than 99 mailboxes, the software provides a CSV-based mailbox loading option. You can upload a CSV file containing the mailbox addresses to facilitate mailbox selection for larger migration projects.

Before continuing, verify that the required source mailboxes are included.

Step 5: Connect to the Microsoft 365 Destination Tenant

After configuring the source environment, connect to the destination Microsoft 365 tenant.

The software provides two registration options:

Option 1: Automatic registration

Use the auto-registration option and sign in with the required Microsoft 365 Global Administrator account, following the application’s authentication prompts.

Option 2: Manual registration

Use manual registration and enter the required application details, including the email address, client ID, tenant ID, and client secret.

These application details are obtained when registering and configuring the application in Microsoft Entra ID, formerly Azure Active Directory.

The appropriate registration method depends on the organization’s authentication setup and administrative requirements.

Step 6: Review Destination Mailboxes and Map Mailboxes

After connecting to Microsoft 365, the software displays the available destination mailboxes.

Review the list to ensure that the required destination mailboxes are present and ready for mapping.

Stellar Migrator for Exchange supports automatic mailbox mapping using user IDs. This can reduce the manual effort involved in assigning source mailboxes to their corresponding destination mailboxes.

Once the automatic mapping is complete, review the mappings carefully to ensure that every source mailbox is assigned to the correct destination mailbox.

Correct mailbox mapping is particularly important in larger migrations, where an incorrect assignment could cause data to be transferred to the wrong user account.

Step 7: Configure Migration Scheduling and Options

Before starting the migration, configure the job according to your requirements.

Choose how to run the migration

You can start the migration manually or use the scheduling functionality to configure a migration job to run once, daily, weekly, or monthly.

The scheduler allows you to specify the start time, end time, and duration, helping administrators coordinate migration activity with maintenance windows and business schedules.

Select mailbox data

You can customize the migration scope by selecting a date range or specific folders, depending on the data you need to transfer.

Configure parallel processing

The software allows you to adjust the number of mailboxes processed simultaneously. This setting can help administrators align the migration workload with available network capacity and source and destination environment performance.

These settings should be tested and adjusted based on mailbox size, connectivity, throttling, and the overall migration workload.

Step 8: Review the Migration Summary and Start the Job

Before starting the migration, review the migration summary.

Confirm that the source server, destination tenant, selected mailboxes, mailbox mappings, and configured migration options are correct.

Once everything has been verified, click Start to begin the migration.

Stellar Migrator for Exchange initiates the mailbox transfer and displays the migration status and progress within the application.

Step 9: Monitor Migration Progress in Real Time

During the migration, the software provides visibility into the progress of the job.

The monitoring interface displays information such as completed mailboxes, active transfers, migration progress, and items that require attention.

This centralized view helps administrators track the job without repeatedly switching between different management tools.

However, migration speed is not determined by the software alone. Factors such as mailbox size, internet bandwidth, source Exchange Server performance, Microsoft 365 throttling, and destination service conditions can affect the overall transfer time.

Administrators should monitor the migration and investigate any errors or incomplete transfers before considering the job finished.

Step 10: Verify the Migrated Mailboxes

Completing the migration job is not the final step. Post-migration verification is essential to confirm that the required data has reached Microsoft 365.

Open a representative sample of migrated mailboxes in Exchange Online and check:

• Emails and attachments
• Folder structures
• Calendars and calendar items
• Contacts
• Archive mailbox data, where applicable
• Shared mailbox or public folder data, where included in the migration scope

Also review migration reports and logs for failed, skipped, or incomplete items.

For larger environments, use a documented validation checklist and obtain confirmation from relevant mailbox owners or administrators before decommissioning the source environment.

Stellar Migrator for Exchange: Key Features

Before getting into the migration process, here are some of the notable capabilities of the software:

• Guided migration workflow: Configure and manage the migration process through a structured interface.
• Flexible source and destination configuration: Connect an on-premises Exchange Server to Microsoft 365.
• Mailbox discovery: Detect available source and destination mailboxes.
• Automatic mailbox mapping: Map source and destination mailboxes using user IDs.
• CSV-based mailbox selection: Load mailbox details through a CSV file, useful for migrations involving more than 99 mailboxes.
• Selective migration: Choose specific folders or a date range to migrate.
• Migration scheduling: Run migration jobs manually or schedule them for a specific time, daily, weekly, or monthly.
• Parallel mailbox processing: Configure the number of mailboxes processed simultaneously.
• Real-time monitoring: Track migration progress, completed mailboxes, active transfers, and items requiring attention.
• Trial version: Evaluate the software by migrating up to two mailboxes at no cost.

Final Verdict: Is Stellar Migrator for Exchange Worth Evaluating?

This Exchange Migration tool offers a structured approach to migrating mailboxes from an on-premises Exchange Server to Microsoft 365. Its guided workflow, automatic mailbox mapping, scheduling options, selective migration settings, and centralized progress monitoring can help administrators organize and manage migration projects.

The software is particularly worth evaluating for IT administrators, Microsoft 365 consultants, and managed service providers who want an alternative to managing every migration stage manually through native administrative tools and scripts.

That said, a migration tool is only one part of a successful migration strategy. Organizations should verify permissions, prepare backups, assess network and service limitations, perform a pilot migration, and validate the destination mailboxes before moving to full production deployment.

Our recommendation: If you are planning an Exchange Server to Microsoft 365 migration, start by testing Stellar Migrator for Exchange with its two-mailbox trial. Evaluate the mailbox mapping, migration workflow, monitoring, reports, and the accuracy of the migrated data in your own environment before deciding whether it meets your requirements.