Microsoft re-adding apps I uninstalled

On supported Windows versions, some Microsoft apps such as the new Outlook can be preinstalled or reinstalled by Windows Update or via Mail and Calendar deprecation.

To stop the new Outlook app from being added back:

1. Remove the provisioned (preinstalled/default) Outlook package so Windows Update doesn’t reinstall it:

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

   After this, Windows updates won't reinstall the new Outlook for Windows.
2. Remove the app for all existing users so it disappears from current profiles:

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

3. If Mail and Calendar are triggering the move to new Outlook, remove those apps as well:

      Get-AppxProvisionedPackage -Online | Where {$_.DisplayName -match "microsoft.windowscommunicationsapps"} | Remove-AppxProvisionedPackage -Online -PackageName {$_.PackageName}
      
      Remove-AppxPackage -AllUsers -Package (Get-AppxPackage microsoft.windowscommunicationsapps).PackageFullName
   

4. To prevent users from acquiring new Outlook from Microsoft Store, configure or block Microsoft Store access using the guidance in "Configure access to the Microsoft Store app".

If any of these apps were removed via policy (for example, a policy that removes default Microsoft Store packages), clear that policy before attempting to reinstall them from the Store or via management tools.

Note: Removing or uninstalling the Microsoft Store app itself is not supported; only access to it can be configured or blocked.

References:

• Control installing and using new Outlook
• Policy-Based Removal of Pre-installed Microsoft Store Apps
• Removing, uninstalling, or reinstalling Microsoft Store app isn't supported
• Find, install, and uninstall applications from the Microsoft Store