How to Migrate Exchange 2016 to Microsoft 365: Step-by-Step Guide
Question details
The user needs to plan and execute a migration from an on-premises Exchange Server 2016 environment to Exchange Online in Microsoft 365 while preserving mailboxes, domains, mail flow, and user access.
- Product
- Microsoft Exchange Server 2016 and Microsoft 365 Exchange Online
- Device & OS
- not provided
- Scenario
- An organization is moving from on-premises Exchange Server 2016 to Exchange Online and needs to choose the right migration path, configure coexistence, and migrate mailboxes with minimal disruption.
- Observed behavior
- The migration must preserve mailboxes, domains, mail flow, and user access, and the user needs clear prerequisite and execution guidance.
Before starting, verify that you have Microsoft 365 global admin access, confirm Exchange 2016 version and mailbox sizes, and document accepted domains, DNS records, certificates, and firewall requirements because the migration method depends on these details.
Assess Your Exchange 2016 Environment and Choose a Migration Method
Use this first to compare cutover, staged, hybrid, and IMAP migration options based on mailbox count, size, coexistence needs, and licensing.
Go to admin.microsoft.com, sign in with a global admin account, and open Billing > Licenses to confirm Exchange Online licenses are available for all users.
Open the Exchange Management Shell and run Get-ExchangeServer | Format-List Name,Edition,AdminDisplayVersion and Get-MailboxDatabase | Format-List Name,DatabaseSize to document your current environment.
In Microsoft 365 admin center, open Setup > Migration and review the options: cutover for fewer than 2,000 mailboxes, staged for older Exchange versions, hybrid for long-term coexistence, and IMAP only for limited non-Exchange scenarios.
Perform a Cutover Migration for Small Exchange 2016 Organizations
Use this method when you have fewer than 2,000 mailboxes and can move all mailboxes to Microsoft 365 during a planned switchover window.
Run a Hybrid Migration for Staged Exchange 2016 to Microsoft 365 Coexistence
Use this method for larger organizations that need to move mailboxes in batches while keeping mail flow, free/busy, and directory synchronization active between Exchange 2016 and Exchange Online.
Need an Office Suite After Your Exchange 2016 to Microsoft 365 Migration? Try WPS Office
After migrating Exchange 2016 to Microsoft 365, WPS Office provides a free, lightweight office suite with familiar editing tools and strong Microsoft Office format compatibility, so your team can open, edit, and share Word, Excel, and PowerPoint files without extra licensing costs.
Frequently Asked Questions
What is the easiest migration method for a small Exchange 2016 organization?
For fewer than 2,000 mailboxes, use cutover migration from Exchange admin center > Recipients > Migration, then update MX records after final synchronization.
Do I need a hybrid configuration to keep some mailboxes on Exchange 2016?
Yes. Run the Exchange Hybrid Configuration Wizard and sync identities with Microsoft Entra Connect so you can migrate in batches while maintaining coexistence.
Can WPS Office open Outlook data or replace Exchange 2016?
No. WPS Office is a desktop office suite, not an Exchange server or email migration tool. Use Microsoft 365 admin tools for Exchange migration and use WPS Office for Word, Excel, and PowerPoint files.
How do I verify mail flow after moving mailboxes to Microsoft 365?
Use the Exchange admin center mail flow dashboard and message trace in Microsoft 365 to test inbound and outbound mail after updating MX and Autodiscover records.
When can I decommission Exchange 2016 after the migration?
Only after all mailboxes are migrated, public folders and relay services are moved, directory synchronization is stable, and management of Exchange attributes is no longer required.
