Microsoft manifested something that had been a long time coming: forced installation of the new Outlook app on Windows 10 PCs by way of the February 2025 mandatory update. This is the next step in Microsoft’s push to make the new Outlook commonplace.

The new Outlook app on Windows 10 is poorly received among users. Users have noted slower performance, cloud storage of emails, and invasive ads. Resources are available to learn about data usage and optimize the new app.

How to prevent Outlook from installing with Windows 10 KB5051974, which is February 2025's big cumulative update (mandatory).

Microsoft previously only made this measure known via an announcement in the Microsoft 365 Admin Center. But as of update KB5051974, which is mandatory, the new Outlook app has been force-installed for Windows 10 users on versions 21H2 and 22H2.

Microsoft has released the KB5051974 cumulative update for versions 22H2 and 21H2, adding security fixes and patching a memory leak. However, as reports, the update also includes a surprise: the new Outlook for Windows app.