Windows is a widely used operating system for years without a doubt, Microsoft never issued any vital info on a lighter OS version similar to Chrome OS that comes with Google Chromebook. Considered as highly secure Chromebooks are powered by cloud and deliver necessary features like Data Encryption, Verified Boot, Sandboxing, etc.
In past, Microsoft had tried to do something similar through Windows RT and Windows 10 S. But due to its limitations, it does not turn out into a streamlined successful platform for a broader audience. Google introduced Chrome OS seven years ago that uses the Chrome Web Browser as a principal interface, allowing users to work on a popular web application. The popularity is wide enough to affect Windows as it does not has any lighter version that can let the manufacturer bring something affordable.
According to the source Microsoft is working on a fast-paced schedule to push Lite OS for the Build Conference in May. Microsoft may start testing the new OS this summer. The Lite OS will target both light and heavy users, yet it unclear whether Microsoft will keep Windows 10 OS as reserved for high-end users and separately trade Lite OS to low-end users.
Lite OS will target Universal Windows Platform and Progressive Web Apps and Microsoft is also looking into Win32 support. A lot of features and info on Windows Lite OS is still a rumor, for example, the UI and its features.
Source: Petri