Should Open XML fail to become an ISO standard, it will be a major blow to Microsoft's efforts to paint itself as an advocate or open standards. Microsoft is attempting to fast track the adoption of Open XML as an ISO standard to combat a global backlash against de facto standards, such as Microsoft's Office formats, by governments and large corporations which fear a reliance on one vendor and format.

Open Document Format became an ISO standard last year and is the default format of open source Office competitors such as OpenOffice and StarOffice, which some believe threaten take up of Microsoft's new Office 2007 suite. The open source community has developed a Microsoft Office plugin, with Microsoft's blessing, that allows Office 2007 to work with the open source Open Document Format. Work is also underway on an Open XML plugin for OpenOffice.

While Microsoft describes Open XML as open source, it's not licensed in a fashion that proponents of open source licensing would recognise as being open. Rather than granting users open source-like rights to the format, the license consists of a promise by Microsoft not to sue those who use the format. It also leaves the standard open to drop in proprietary code.

The news of ISO objections comes as another blow to Microsoft as two more US states - Texas and Minnesota - consider turning their backs on Microsoft and adopting open document formats under separate bills put to the state legislatures. By as early as next year they could join Massachusetts, the first US state to mandate the use of ODF as the standard format for all state agency documents.{moscomment}