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

Microsoft announced last year that it would be retiring the Windows Mail & Calendar apps in favor of the new Outlook at the end of 2024. As of January 1, these apps are no longer functional and will refuse to send or receive any more emails.

Starting next month, Microsoft will begin forcibly installing its new Outlook email client on all Windows 10 devices. This move will occur in two phases. The first phase of the rollout will begin on 28 th January 2025 with the release of an optional Windows 10 update. This update will include the new Outlook for users who choose to install it.

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

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.