The Mac OS Startup Screen is the initial image displayed on a Classic Macintosh following the "Happy Mac" icon that indicates bootable media with a proper System folder has been found. It is the first image displayed by the operating system to indicate it is loading onto the hardware. With specific extensions such as MACSBug installed, further text was also displayed in the dialog. In later versions of the operating system, further loading text was also displayed in this space, including "Extensions Off" if the shift key was held down during the boot process.