The founding of the organization was largely seen as a response to the collaboration between AT&T and Sun Microsystems on UNIX System V Release 4, and a fear that other vendors would be locked out of the standardization process. This led Scott McNealy of Sun to quip that "OSF" really stood for "Oppose Sun Forever." The competition between the opposing versions of Unix became known as the Unix wars. AT&T founded the UNIX International (UI) organization later that year as a counter-response to the OSF.
OSF's standard Unix implementation was known as OSF/1 and was first released in 1992. For the most part, it was a failure; by the time OSF stopped development of OSF/1 in 1994, the only vendor using OSF/1 was Digital, which rebranded it Digital UNIX (later known as Tru64 UNIX after Digital's acquisition by Compaq).
By 1993, it had become clear that the greater threat to Unix vendors was not each other as much as the increasing presence of Microsoft in enterprise computing. In May, the COSE initiative was announced by the major players in the Unix world from both the UI and OSF camps: Hewlett-Packard, IBM, Sun, Unix System Laboratories, and the Santa Cruz Operation. As part of this agreement, Sun became an OSF member, and OSF submitted Motif to the X/Open Consortium for certification and branding.
In March 1994, OSF and UI merged into a new organization, retaining the OSF name and incorporating COSE's development model into its new Pre-Structured Technology (PST) process. It also assumed responsibility for future work on the COSE initiative's Common Desktop Environment (CDE). In September 1995, the merger of OSF/Motif and CDE into a single project, CDE/Motif, was announced.