Designed to replace the current Mail and Calendar apps, the new Outlook can only be removed after it's been installed.

For several months now, Microsoft has been urging Windows users to switch over to the new Outlook app, with classic Outlook recently getting an official “death date”. Many aren’t happy about this, holding off on jumping ship as long as they can — but the clock is ticking down.

Microsoft won't let you block lock new Outlook on Windows 10 (auto-install) but you can remove it via PowerShell.

Microsoft will automatically install its new Outlook client on Windows 10 PCs with next month’s Patch Tuesday update.

The new Outlook will be automatically delivered to all computers running Windows 10. It is the same version of the program already installed in Windows 11, provided users continually download all updates.