File with a .SCR extension contains a Windows screensaver in an executive form. It means, that it is being run in the moment the file is being opened. A screensaver may contain an animation, a vector graphic, a slide show and also sound effects.

SCR files are contained usually in the main directory of Microsoft Windows system. They are run automatically, according to the settings within the screensaver control panel, where also certain elements of a screensaver can be custom-adjusted.