The Ancora patent in question (US Patent 6,411,941) is dated June 25, 2002, and Mullor claimed he approached Microsoft in 2003 to discuss the "benefits Microsoft could realize by using it," but Microsoft wasn't interested. He believes Microsoft developed the technology after his offer. Ancora filed a lawsuit against Dell, HP, and Toshiba, alleging that the companies were infringing on its patent by selling computers with Windows Vista preactivated, which is possible thanks to one of Microsoft's anti-piracy technologies, System Locked Preinstallation (SLP). Mullor was still a Microsoft employee when Ancora filed the suit against the PC makers; he was hired as a program manager in the Windows Security Group in November 2005. Mullor said he informed Microsoft about his patent in his résumé and employment agreement.

In June 2008, four days after Microsoft accused him of trying to hide his downloading activities of internal documents, Ancora filed its patent lawsuit. In September 2008, Microsoft intervened as a party-defendant in the case and fired Mullor. The documents Mullor is accused of downloading from Microsoft before Ancora filed the lawsuit included information on the SLP and the upcoming Windows 7 operating system, according to Microsoft's complaint. Microsoft goes on to say that they were downloaded onto Mullor's company-issued laptop, after which Mullor allegedly deleted them, and then tried to hide his tracks by using software that overwrites deleted files.

In January 2009, Microsoft filed its own lawsuit in King County Superior Court in Seattle, which claims Mullor wrote in his October 2005 Microsoft employment application that he no longer worked for Ancora because it was out of business. The company said he failed to disclose when hired that he believed SLP infringed on the Ancora patent. The patent case was scheduled for trial in a Los Angeles federal court on January 26, 2010, but it looks like that meeting is no longer necessary.