Aimed at the education market, Windows 10 S is a version of Windows that comes pre-installed on some laptops. Initially available separately, Windows 10 S only runs apps downloaded from the Microsoft Store. OneDrive cloud storage is included, Edge is the default Web browser, and schools can provision machines from a USB drive. Microsoft has not divulged the meaning of "S," but "Secure" has been suggested.
Windows 10 in S Mode
Windows 10 S was introduced in 2017; however, the April 2018 update officially changed the name from "Windows 10 S" to "Windows 10 in S mode."
Switch Out But Not Back
In order to run an app that did not come from the Microsoft Store, Windows can be taken out of S mode and switched to Windows 10 Home or Pro. However, users cannot revert to S mode later on.
A Chromebook Competitor
Introduced on Microsoft's Surface Laptop, Windows 10 S was designed to compete with Chromebooks, which have similar functionality. As of 2020, companies such as HP, Dell, Asus and Acer have debuted Windows 10 S laptops. See Surface Laptop