Microsoft is currently testing a new functionality in Windows 10 that prevents you from installing any desktop apps – unless they come from the official store.
The latest Windows Insider preview build of Windows 10 includes options to only allow apps from the Windows Store, but the feature appears to be set as allowing apps from anywhere to install by default. It could be a useful feature to enable on a family PC to prevent rogue desktop apps from being installed.
MSPoweruser reports the feature will notify users with a warning anytime they attempt installing desktop apps. The notification will be accompanied by a message reminding users the Windows Store is the only “safe and reliable” place to satisfy your software needs.
While as of now the feature is disabled by default, users can head to the Apps and Feature category in Settings to enable it.
You will have the option to allow or block the installation of Win32 apps altogether, as well as the alternative to give priority to Windows Store apps without blocking standard desktop software – this will likely prompt you to approve installation any time you try running non-store apps.