California asked the federal judge overseeing Microsoft's antitrust oversight agreement to extend a section of it by three years to 2012.
Under the 2002 settlement, Microsoft was required to create a Microsoft Communications Protocol Program, or MCPP, to allow rival operating systems to communicate with Windows.
"Clearly this has not happened," attorney Stephen Houck, speaking for California, told the hearing in U.S. District Court for the District of Columbia. "None of the parties in their filings claim that the MCPP has been successful."
District Judge Colleen Kollar-Kotelly issued no immediate ruling.