Windows 1.0 BYTE demo

Windows 1.0 "BYTE" build is the earliest build of Microsoft Windows confirmed to exist. It was shown in the 1983-12 issue of BYTE Magazine, though the build itself is much older and was already obsolete by the time the article was published. Microsoft redesigned the user interface sometime before the official announcement on 1983-11-10, and the new UI had little in common with this early one.

The interface is very similar to Microsoft's DOS applications such as Word and Multiplan which were also released or in development at the time, with a command bar at the bottom of the screen, and featured overlapping windows that were later replaced by tiling windows. It was demonstrated to certain members of the press someday after 1983-05. It remains unclear whether the build and applications demonstrated were actually fully functional or just cleverly crafted to create an illusion of a working system.

Photos of various MS-DOS computers running this build were also published.

Screenshots
 WinB83_1.png|Desktop and Session Control Menu WinB83_2.png|BASIC86 Win1983p4.jpg|Microsoft Piano, bundled with Microsoft Mouse software for DOS, is used as an example of an uncooperative app Win1983p5.jpg|Microsoft Word Win1983p6.jpg|Word and Multiplan side-by-side Win1983p10.jpg|Graph maximized Win1983p11.jpg|Graph dialog box Windowsbyte4.png|Overlapping Windows WindowsByteBasic86.png|BASIC86 (Screen in color) Win1983pcs.jpg|Windows could already run on all these machines, including an Apple II with a PC emulator card 