In the reexamination proceeding initiated earlier this year by the Public Patent Foundation, the United States Patent and Trademark Office has rejected all of the claims of Microsoft's patent on the FAT file system, which Microsoft describes as "the ubiquitous format used for interchange of media between computers, and, since the advent of inexpensive, removable flash memory, also between digital devices."

Relying predominantly on evidence provided by PUBPAT when the reexamination was requested, the Patent Office made multiple rejections of the Redmond, WA based software giant's patent. Microsoft has the opportunity to respond to the Patent Office's rejection, but third party requests for reexamination, like the one filed by PUBPAT, are successful in having the subject patent either narrowed or completely revoked roughly 70 percent of the time.