Ways to Migrate Multiple Email Accounts to Microsoft 365

Microsoft 365 is one of the topmost platforms for businesses as it provides a reliable emailing system without initial infrastructure investment. If you are looking to migrate your existing multiple email accounts(mailboxes) to Microsoft 365, it is important to select the migration method beforehand.This will help you alleviate issues and successfully move your mailboxes and other data to Microsoft 365.In this post,we will be mentioning various methods to migrate mailboxes to Microsoft 365.It is vital to choose the best method that suits your organization’s needs.

Why Migration to Microsoft 365 is Important?

Migrating to Microsoft 365 offers various benefits as compared to on-premises Exchange or other IMAP-enabled email systems. Some of the benefits are listed below:

  • Microsoft 365 offers extended scalability without any significant infrastructure investment.
  • There is no need to maintain servers, hardware, and any other systems. Investing in Microsoft 365 provides access to all the features offered by on-premises and many other facilities.
  • You do not need to update the latest software versions or worry about server downtime situations. Microsoft will take care of the updates automatically.
  • There are no security concerns due to technical faults or disasters as you stay assured with Microsoft enterprise-grade data security.

Ways to Migrate Mailboxes to Microsoft 365

Here are some methods to migrate mailboxes to Microsoft 365. You can choose the one depending on your needs.

Method 1: Export Mailboxes to PST and Import the PST Files into Microsoft 365

If you have a small number of mailboxes, you can export them to PST files and import these files into Microsoft 365 directly. If you are using Exchange 2010 SP1 or above versions, the New-MailboxExportRequest PowerShell cmdlet can be used to export mailboxes to PST. Once the mailboxes are exported, you can easily import PST into Microsoft 365 account.

Method 2: Export Mailboxes to Microsoft 365

If you have a large number of mailboxes, then you can use the express, staged, or hybrid migration techniques.

  • Express or Cutover Migration – If you have less than 2000 mailboxes, express migration can be the best way forward. This migration method can be performed with Exchange Server2010,2013,or 2016. While Microsoft recommends migration of 150 users or less at a time as migrating up to 2000 mailboxes can take a lot of time. This type of migration involves several steps such as verification of domain, running directory synchronization, providing Microsoft 365 licenses, migrating user mailbox data, and updating DNS records.
  • Staged Migration – This method is suitable for organizations that use Exchange 2007 or 2003. It can be used for migrating more than 2000 mailboxes.
  • Hybrid Migration –This method has become the first preference for businesses as it offers the best user experience. It provides the same environment for Microsoft 365 and on-premises Exchange Server. It supports Exchange 2013 or 2010 and allows to migrate more than 150-200 mailboxes. The only downside of the hybrid method is that it relies heavily on directory synchronization.

Method 3: Migrating PST Files to Microsoft 365 with Import Service

Import service is provided by Microsoft 365 to support the migration of multiple PST files to Microsoft 365 mailboxes. This service can be used in two ways – uploading PST files to Microsoft cloud or mailing the PST files in a drive to Microsoft.

  • Drive Shipping – This is a lengthy process as it involves savingyour PST files in a storage drive, shipping the drive to Microsoft, and waiting for them to upload those files to Microsoft cloud. To perform this method, you need to download the PST import tool and secure the storage key from Microsoft.
  • Network Upload – This method is comparatively easier to perform. Network upload method involves the installation of Azure AzCopy, uploading PST files to Microsoft cloud, creating PST import mapping files, importing PST into Microsoft 365, filtering the data, and performing the import process.

Method 4: Migrating Emails from IMAP-enabled Email System

This method can be used to migrate multiple mailboxes from different types of IMAP-enabled email clients. This option is available in theMicrosoft Admin Center and allows to migrate mailboxes to Microsoft 365.

Before choosing this method, you should know its limitations:

  • IMAP migration can only move inboxes and other mail folders to Microsoft 365. Other mail items, such as calendars, contacts, tasks, calendars, etc. cannot be moved.
  • The migration of up to 50,000 mailboxes is supported by this method.
  • Any mail item exceeding 35 MB is skipped during the migration process and would not be moved to Microsoft 365 mailbox.

In addition, this method also needs access to user mailboxes. If the users are not aware of their email passwords, they would not be able to access their email account during or after the migration.

Method 5: Migrate Multiple Mailboxes (PST Files) to Microsoft 365

Migrating mailboxes to Microsoft 365 is a voluminous task using the manual methods and requires multiple attempts to achieve a successful migration. It requires technical expertise, lot of time, and efforts to deal with the migration process. The best way to avoidall these hassles is to migrate mailboxes (PST) with the help of Stellar Migrator for Outlook. It helps you import PST files directly into Microsoft 365 with complete integrity. It is an easy-to-use tool that helps you to migrate PST files from multiple systems to Microsoft 365 and customize the migration according to your business needs. Here is how it works:

  • Step 1: Launch Stellar Migrator for Outlook and click List Profiles to choose the PST files manually. Click Scan to initiate analysis of PST files.
  • Step 2: Once the scanning process is completed, select the mail items and folders to be uploaded to Microsoft 365 and click Migrate Mailbox.
  • Step 3: Provide the username and password of licensing account.
  • Step 4:Select Office 365 and click Next.
  • Step 5: Provide the credentials of Microsoft 365 and click Migrate. The tool will establish a secure connection with Microsoft365 and starts migrating PST files to Microsoft 365 account.
  • Step 6: A message will be displayed once the mailboxes are migrated successfully to Microsoft 365 account.


While there are various manual approaches to migrating email accounts from existing infrastructure to Microsoft 365, a ready-to-use solution, like Stellar Migrator for Outlook can work wonders for you. It helps you eliminate all the manual hassles, wastage of time and resources, and many other challenges. The software can directly migrate PST files to the Microsoft 365 account in a few clicks with complete integrity. Try Stellar Migrator for Outlook today.

Author: 9TP

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