Control installing and using new Outlook

This article provides guidance for administrators who want to control the installation of the new Outlook in an organization and how users access and use the app.

Prevent users from switching to new Outlook

Some administrators might choose to hide the Try the new Outlook toggle from appearing in the classic Outlook for Windows until the organization is ready to migrate the Outlook app.

Hiding the "new Outlook" toggle is available as a cloud policy in the Microsoft 365 Apps admin center. To set up the policy:

1. Sign in to the Microsoft 365 Apps admin center.
2. Under Customization, select Policy Management.
3. Select Create.
4. Search for the Hide the "Try the new Outlook" toggle in Outlook policy, and then enable it.

Alternatively, you can use the following Windows registry key to hide the Try the new Outlook toggle:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\General]
"HideNewOutlookToggle"=dword:00000000

To later enable the policy, set the registry key to 1:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\General]
"HideNewOutlookToggle"=dword:00000001

For more information about this process, see the Use the registry to enable or disable the "Try the new Outlook" toggle in classic Outlook section of "Enable or disable user access to Outlook for Windows in Exchange Online."

Block new Outlook preinstallation on Windows

Windows 11

Windows 11 builds later than 23H2 have the new Outlook app preinstalled for all users. Currently, there isn't a way to block the new Outlook from being installed in these builds. If you prefer not to have new Outlook show up on your organization's devices, you can remove it after it's installed during the update.

To remove the app package, run the Remove-AppxProvisionedPackage cmdlet by using the PackageName parameter value, Microsoft.OutlookForWindows. After the package is removed, Windows updates won't reinstall new Outlook.

Run the following command in Windows PowerShell:

Remove-AppxProvisionedPackage -AllUsers -Online -PackageName (Get-AppxPackage Microsoft.OutlookForWindows).PackageFullName

Additionally, remove the following Windows orchestrator registry value:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsUpdate\Orchestrator\UScheduler_Oobe\OutlookUpdate

For any device that installed the March 2024 Non-Security Preview release (or later cumulative update) for Windows 11, version 23H2, Windows Orchestrator respects the deprovisioning cmdlet. Therefore, it's not necessary to remove this registry value in this case.

Windows 10

The new Outlook app is automatically installed on Windows 10 devices as part of the following updates:

• The optional Windows 10 release on January 28, 2025
• The monthly security update release for Windows 10 on February 11, 2025

To prevent the installation of new Outlook on your organization's devices, add the following registry value:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsUpdate\Orchestrator\UScheduler_Oobe

Then, add a REG_SZ registry setting that's named BlockedOobeUpdaters, and give it a value of ["MS_Outlook"].

To remove the app package after it's installed, run the Remove-AppxProvisionedPackage cmdlet by using the PackageName parameter value, Microsoft.OutlookForWindows.

Run the following command in Windows PowerShell:

Remove-AppxProvisionedPackage -AllUsers -Online -PackageName (Get-AppxPackage Microsoft.OutlookForWindows).PackageFullName

After the package is removed, Windows updates won't reinstall new Outlook.

User installations

In cases of user installations (for example, if users use the toggle to install the new Outlook for Windows), run Remove-AppxPackage. The AppxPackage cmdlets are used to manage applications for current users, and AppxProvisionedPackage cmdlets are used to manage default applications for both current and future users of the system.

Run the following Windows PowerShell command to remove the new Outlook for Windows for all users:

Remove-AppxPackage -AllUsers -Package (Get-AppxPackage Microsoft.OutlookForWindows).PackageFullName

Block new Outlook installation as part of Mail and Calendar deprecation

Users can switch to new Outlook from the Mail and Calendar apps that are included in Windows. Support for Windows Mail and Calendar ended on December 31, 2024. We're automatically switching active users to the new Outlook app.

If you want to block users from getting the new Outlook from Windows Mail and Calendar applications, you can uninstall these apps from the user's devices.

To uninstall the apps, follow the instructions in Remove-AppxProvisionedPackage to remove the app package by using the PackageName parameter that has the value, microsoft.windowscommunicationsapps.

Run the following Windows PowerShell command:

Get-AppxProvisionedPackage -Online | Where {$_.DisplayName -match "microsoft.windowscommunicationsapps"} | Remove-AppxProvisionedPackage -Online -PackageName {$_.PackageName}

To remove the Mail and Calendar apps for current users, run the following Remove-AppxPackage command in Windows PowerShell:

Remove-AppxPackage -AllUsers -Package (Get-AppxPackage microsoft.windowscommunicationsapps).PackageFullName

Alternatively, you can remove the apps through Intune or by following the instructions in Uninstall applications with Configuration Manager.

Prevent users from acquiring new Outlook from Microsoft Store

The new Outlook for Windows app is also available in the Microsoft Store. To prevent users from downloading the app from the store, you can block store access by following the instructions in Configure access to the Microsoft Store app.

Opt out of new Outlook migration

Admins can disable the user setting for automatic migration to prevent users from being switched to the new Outlook.

Policy: Manage user setting for new Outlook automatic migration

The policy can be configured by using the following values:

• Not set (Default): If you don’t configure this policy, the user setting for automatic migration remains uncontrolled, and users can manage it themselves. By default, this setting is enabled.
• 1 (Enable): If you enable this policy, the user setting for automatic migration is enforced. Automatic migration to the new Outlook is allowed, and users can't change the setting.
• 0 (Disable): If you disable this policy, the user setting for automatic migration is turned off. Automatic migration to the new Outlook is blocked, and users can't change the setting.

Configuring the policy using the Windows registry

To disable automatic migration:

[HKEY_CURRENT_USER\Software\Policies\Microsoft\office\16.0\outlook\preferences]
"NewOutlookMigrationUserSetting"=dword:00000000

To enable automatic migration:

[HKEY_CURRENT_USER\Software\Policies\Microsoft\office\16.0\outlook\preferences]
"NewOutlookMigrationUserSetting"=dword:00000001

Setting in Group Policy

You can download the latest Group Policy Administrative Template file from the Microsoft Download Center.

Setting in Cloud Policy

You can also set this policy through the Cloud Policy service from the Microsoft 365 Apps admin center. For more information about Cloud Policy, see Overview of Cloud Policy service for Microsoft 365.

Conditional access to the new Outlook App

Many organizations have common access concerns that Conditional Access policies can help resolve. For example:

• Requiring multifactor authentication for users
• Blocking or granting access from specific locations
• Blocking risky sign-in behaviors
• Requiring organization-managed devices to be used

A more granular control can be offered by using OWA Mailbox Policies together with the ConditionalAccessPolicy parameter. For example, when users are on noncompliant devices, OWA mailbox policies limit their capabilities. For example, restricting attachments.

To learn more about Conditional Access and how to configure it, follow the instructions in Require compliant, hybrid joined devices, or MFA to grant or block access. To configure OWA Mailbox Policies, check OWA Mailbox Policy - Conditional Access Policy.

Block mailbox access on new Outlook

Users might acquire the new Outlook app through various flows, as outlined in the previous sections. To prevent mailbox access from the new Outlook, regardless of how users acquire it, use an Exchange mailbox policy to block organization (work or school) mailboxes from being added to the app. This policy serves as the final block, making sure that users can't use their work or school accounts even if they have the app on their device.

Mailbox policies are applied to the work or school email account and not at the device or app level. Therefore, to prevent users from using the app together with other accounts that aren't their work or school email account, we recommend that you block access to the app (as discussed in previous sections).

To manage mailbox access, follow the instructions in Enable or disable user access to Outlook for Windows in Exchange Online.

How to enable new Outlook for Windows Public Preview in DoD and GCC High

The audience for this article is strictly limited to DoD/DoW and GCC High tenants.

New Outlook for Windows Public Preview gives organizations using the GCC High and DoD sovereign instances an early opportunity to validate the new Outlook experience in their environment, identify blockers, and provide feedback before broader availability. The Microsoft 365 roadmap item 564913. identifies the feature as “New Outlook for Windows for GCC-H and DoD,” with GCC High and DoD as the cloud environments.

1. Identify where you want to test the Public Preview of new Outlook

New Outlook remains off by default, requires administrative action to enable supported sovereign environments, and does not automatically switch users from classic Outlook. Organizations in both GCC-High and DoD can participate in the Public Preview using policies and by enabling specific devices.

We recommend starting with a test tenant that can exercise realistic scenarios, including sizable mailboxes, shared mailboxes, calendar workflows, attachments, Teams-integrated flows, People, Settings, and Copilot chat.

2. Install the new Outlook client

New Outlook is installed with Windows 11. If you had previously removed the app from devices, it will need to be reinstalled. Install new Outlook for Windows using the installer links at Deployment overview for the new Outlook for Windows | Microsoft Learn.

The classic Outlook toggle will not be available during the initial Public Preview, so users should not expect to access the Preview by toggling from classic Outlook. The toggle is expected to rollout in classic Outlook in August 2026. Once the toggle is available, you will need to ensure that it is enabled in classic Outlook to exercise that migration path. Note the toggle will only display if the classic user has all accounts in the same sovereignty (including the subscription account).

3. Configure the preview environment

Once the application is installed on the device, to determine which Preview environment your tenant is using, the goal is to configure the registry key for your cloud as follows:

GCC High

[HKEY_CURRENT_USER\Software\Microsoft\office\16.0\outlook]

"NewOutlookForWindowsCloudType"=dword:00000003

DoD

[HKEY_CURRENT_USER\Software\Microsoft\office\16.0\outlook]

"NewOutlookForWindowsCloudType"=dword:00000004

These registry keys are required to point the new Outlook client to the correct sovereign cloud environment. If not set, new Outlook will default to the Worldwide end point and will not find your accounts.

The options available to set up the above are:

• Preferred option: CPS (Cloud Policy Setting)

• Future option (not available yet): GPO (Group Policy)

• Alternatively, you can use any other direct method your organization is currently using to set up Windows registry keys (e.g., via PowerShell script via the console, etc.)

Policy Setting via CPS:

To set up the policy:

1. Sign in to the Microsoft 365 App Admin Center:

   • GCC High: https://config.office365.us

   • DoD: https://config.apps.mil

2. Under Customization, select Policy Management.

3. Select Create.

4. Set up the policy: follow the steps in Policy Creation UI as described below.

4. Controlling access

Ensure that new Outlook can be used by the user. Your organization may have previously blocked access in your tenant. Instructions to Allow/Block individual user access and shared mailboxes access to new Outlook are available here: Enable or disable access to Outlook for Windows | Microsoft Learn. Note that both the shared mailbox and the user accessing the shared mailbox will need to have access to new Outlook.

Set the policies to enable the toggle for users to ensure you can test the toggle experience when the toggle becomes available (est by mid-August 2026 via June fork). Instructions to control migration from classic Outlook to new Outlook are here - Control Installing and Using New Outlook | Microsoft Learn.

We recommend you also take the time to compare classic Outlook policies to new Outlook policies: Map Classic Outlook Policies to New Outlook - Outlook | Microsoft Learn.

5. Add accounts after the tenant is enabled

With the prerequisites in place (app installed, environment set, mailbox enabled and user can toggle) you are ready to start up the app. When Outlook opens it will request you add an account. Add an enabled account from your tenant. The first account added becomes the default primary account, and additional accounts can be added afterward via the Add account flow at the bottom of the Folder pane. Auto mapped mailboxes will populate if configured.

All accounts must be in the same sovereign cloud environment but not necessarily from the same tenant. Microsoft is working on multi-environmental support (e.g. accounts can be added from Worldwide, GCC-H *and* DoD into the same client), but that capability is not yet available. The roadmap will be updated when we have an estimated availability date.

If you would like to block users from adding accounts from different tenants, you can do so with this policy example.

6. Exercise real-world scenarios

Use the Public Preview to validate workflows that matter to your organization. Focus on:

• Adding accounts with sizable mailboxes.

• Accessing and using shared mailbox folders.

• Using Search.

• Sending and receiving attachments with images.

• Scheduling and editing meetings and meeting series.

• Using the People app.

• Using integrated flows with Teams.

• Viewing and changing Settings.

• Using Copilot chat.

Include pilot users who can exercise unique workflows. Enroll a small set of champions who can help identify issues unique to their business area, such as delegates and users who rely on shared mailboxes or specialized organizational processes.

7. Use classic Outlook side-by-side

During the Preview and throughout your adoption process, we recommend users run classic Outlook and new Outlook side-by-side to maintain productivity. Users can switch back and forth or run them concurrently. This helps to familiarize users with new Outlook. Pin both apps to the taskbar to simplify access.

Ask pilot users to stay in the new Outlook as much as possible, and when they return to classic Outlook, capture why they needed to do so. This feedback helps identify blockers and helps prioritize product development efforts.

8. Submit feedback to the right channel

There are two main types of feedback:

1. Feature not functioning correctly — Submit in-app feedback when you encounter product issues. This collects user verbatims that are available in the Microsoft 365 admin center for you and to the Outlook team.

2. Product does not yet meet your needs — If a workflow requires functionality that is not available in new Outlook, capture your needs and work with your CSAM/CSA to validate it against roadmap, release notes, and feature comparison resources to see if it is in development or rolling out.

9. Prepare for migration

Use the Preview period to begin migration preparation. Recommended actions include identifying pre-migration work, performing COM add-in inventory, and working with CSAs through the process. COM add-ins are not supported in the new Outlook and organizations should transition to web add-ins. CSAs can help you in this effort. Ensure that you have a plan for user training and change management.