Bill Gates Announces OS/2 Partnership to Employees

On 16/05/1991, Microsoft co-founder Bill Gates issued an internal memo to employees announcing that the company’s joint development partnership with IBM on the OS/2 operating system was ending. Microsoft and IBM had collaborated on OS/2 since 1985 as a successor to MS-DOS, with the goal of creating a protected mode operating system for next generation personal computers. By the early 1990s, however, differences emerged over technical direction, user interface strategy, and product timelines. IBM continued focusing on OS/2, while Microsoft increasingly prioritized Windows as its primary platform. In the memo, Gates explained that Microsoft would shift its development efforts toward Windows, including work that would become Windows NT. The announcement clarified that Microsoft would continue supporting existing OS/2 commitments but would no longer treat OS/2 as its main future operating system. At the time, Microsoft was preparing updates to Windows 3.x and advancing a new 32-bit architecture under development led by Dave Cutler, which later appeared as Windows NT in 1993. The decision marked a formal break in one of the most significant software partnerships of the 1980s. Following the split, IBM continued developing OS/2 independently, releasing versions such as OS/2 2.0 in 1992, while Microsoft focused on Windows 3.1, Windows for Workgroups, and Windows NT. The divergence shaped the personal computer operating system market throughout the early 1990s, with Windows adoption expanding rapidly across PC manufacturers.