Microsoft scored a big win in April when its Open Office XML format got ISO's approval to become a global standard but now the storm clouds have gathered and the format is again facing some opposition. India, Brazil, South Africa and Venezuela have made a complaint regarding the standardization of Open XML claiming that the format hasn't been analyzed enough and that it is not fully compatible with other document formats.

Open XML was intensely opposed before getting ISO's OK as supporters of the Open Document Format (ODF) questioned the logic of having two document standards. Now, with this new complaint, Microsoft's Open XML will have to wait for a decision before being widely adopted.