Microsoft lost the fifth-biggest patent judgment in U.S. history Wednesday in a case involving antipiracy software. A Rhode Island federal court jury slammed the software giant with a $388 million verdict for willfully infringing a patent owned by Uniloc Singapore Private Ltd. and Uniloc USA Inc.

The “product activation” feature in question prevents a single copy of a software program from being used on multiple computers by requiring users to register the software on a specific machine before using it.

Uniloc first filed suit in 2003, and last August the Federal Circuit reversed a lower court decision granting summary judgment to Microsoft. The court remanded the case, and the trial began in late March.

“We are very disappointed in the jury verdict,” Microsoft spokesman David Bowermaster said in a statement. “We believe that we do not infringe, that the patent is invalid and that this award of damages is legally and factually unsupported. We will ask the court to overturn the verdict.”

Microsoft lost the fifth-biggest patent judgment in U.S. history Wednesday in a case involving antipiracy software. A Rhode Island federal court jury slammed the software giant with a $388 million verdict for willfully infringing a patent owned by Uniloc Singapore Private Ltd. and Uniloc USA Inc.

The “product activation” feature in question prevents a single copy of a software program from being used on multiple computers by requiring users to register the software on a specific machine before using it.

Uniloc first filed suit in 2003, and last August the Federal Circuit reversed a lower court decision granting summary judgment to Microsoft. The court remanded the case, and the trial began in late March.

“We are very disappointed in the jury verdict,” Microsoft spokesman David Bowermaster said in a statement. “We believe that we do not infringe, that the patent is invalid and that this award of damages is legally and factually unsupported. We will ask the court to overturn the verdict.”