Windows 1.01

Windows 1.01 is the first retail release of Windows 1.0, released in stores on 20 November 1985 and discontinued on 31 December 2001. According to Microsoft, Windows 1.01 is an "Operating Environment" designed to run on top of MS-DOS, rather than a standalone operating system. Additional applications were bundled with Windows, including Write (a word processor), Paint (a graphics drawing program), Reversi (a game), and various utilities (Clock, Calendar, Calculator among others).

Windows 1.01 initially retailed for $99 in the US. It is designed to run on MS-DOS 2.00 to 5.00. If it is loaded on any version of MS-DOS higher than 5.00 (without using  on  ), it will crash on startup.