Microsoft Pushes Back New Outlook Migration for Enterprises to March 2027

Microsoft has been rolling out several improvements to Outlook recently, including Search Folders enhancements and automapped calendars. Despite promoting the new Outlook experience, it appears the company will not require enterprise users to switch as soon as originally planned.

According to Windows Latest, Microsoft has delayed the automatic migration to the new Outlook for enterprise customers.

Automatic migration to new Outlook pushed back by one year

The company originally planned to begin automatically switching enterprise users to the new Outlook in April 2026. With the updated schedule, that rollout will now begin in March 2027.

This means organizations will not be automatically moved from Outlook Classic to the new Outlook next year as previously expected.

Under the earlier plan, opening Outlook Classic after April 2026 would automatically toggle users into the new Outlook interface. Users would still have the option to switch back to the classic version if they preferred the older client.

Microsoft now says organizations will receive an additional twelve months to prepare their environments before the automatic migration begins.

Outlook Classic support remains available until 2029

Even though Microsoft continues to promote the new Outlook experience, enterprise customers will still be able to use Outlook Classic for several more years.

The company confirmed that Outlook Classic will remain supported until April 2029. This extended timeline gives large organizations additional time to adjust their workflows, test compatibility, and prepare their infrastructure for the transition.

While Microsoft has already moved consumer users to the new Outlook by retiring the Mail and Calendar apps, enterprises are receiving a slower transition because corporate environments typically require longer testing and deployment cycles.

IT administrators can still control the migration

Organizations will be able to manage the switch to the new Outlook through administrative policies and registry settings.

To block the automatic migration, administrators can navigate to the following path:

HKEY_CURRENT_USER\Software\Policies\Microsoft\office\16.0\outlook\preferences

There, they need to create the NewOutlookMigrationUserSetting key and assign it one of the following values:

• 0 = block automatic migration
• 1 = allow automatic migration

These controls allow IT teams to decide when employees should move to the new Outlook experience.

Outlook Classic remains widely used in enterprises

Many organizations still rely heavily on Outlook Classic because it is a native desktop application with strong integration into existing enterprise workflows.

The classic client is often considered faster and more reliable in large mailbox environments, and it still supports certain features that are limited or unavailable in the new Outlook. One of the most commonly cited examples is stronger support for PST files, which many companies still use for archiving and data management.

Microsoft says adoption of the new Outlook continues to grow, but the delay in the forced migration timeline suggests that many enterprise customers are not yet ready to fully transition.

It is also worth noting that Outlook occasionally faces usability issues. Some users recently reported problems such as an invisible cursor in Outlook Classic, which can make navigation and email editing difficult.