Latest Update Force Installs New Outlook Client on Windows 10 PCs

Microsoft released a major cumulative update for Windows 10 versions 22H2 and 21H2 this week. The KB5051974 update delivers important security fixes and automatically installs the new Outlook client on Windows 10 PCs.

Microsoft announced the general availability of the new web-based Outlook for Windows app in August 2024. While Microsoft highlights its advantages, many users still prefer the classic Outlook desktop app. The new Outlook has limited offline support and lacks compatibility with on-premises Exchange accounts and COM add-ins, requiring organizations to switch to web add-ins.

Some users have also reported that the new Outlook desktop app runs slowly on Windows PCs. Additionally, messages sent through the app sometimes fail to be sent properly and get stuck in the draft folder.

How to block forced installation of new Outlook app on Windows 10

The KB5051974 update, which is mandatory for Windows 10 PCs, includes critical security fixes and automatically installs the new Outlook for Windows app. While skipping the update is not recommended, users can prevent the forced installation of the new Outlook client using a registry hack.

• Open the Start menu, search for Registry Editor, and launch it.
• In the Registry Editor, navigate to the following location: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsUpdate\Orchestrator\UScheduler_Oobe
• Right-click the UScheduler_Oobe key in the left pane, navigate to New > String Value, and then name the value BlockedOobeUpdaters.
• Finally, double-click the BlockedOobeUpdaters value and type [“MS_Outlook”] in the Value data field.
• Click Ok to apply the changes and then close Registry Editor.

Microsoft advises that users who have already installed the update can remove the new Outlook app using the following PowerShell command: Remove-AppxProvisionedPackage -AllUsers -Online -PackageName (Get-AppxPackage Microsoft.OutlookForWindows).PackageFullName

The new Outlook for Windows has already replaced the UWP-based Mail and Calendar app on Windows 10 devices. While it will eventually replace the classic Outlook, Microsoft will continue supporting the classic version until at least 2029. In the meantime, both versions can run side by side, allowing users to transition at their own pace.