The U.S. Justice Department is investigating a complaint alleging that Microsoft has violated the antitrust settlement it reached with the federal government in 2002, according to a court filing discussed at a hearing Tuesday.
U.S. District Judge Colleen Kollar-Kotelly asked for more details about the complaint during a regularly scheduled review of Microsoft's compliance with the settlement.
Aaron D. Hoag, a government attorney, declined, saying the complaining company has requesting it not be identified. Microsoft's lawyers said they are cooperating with the probe but declined further comment.
The complaint is related to "middleware," or software that connects different computer programs, according to a court filing made last week. Middleware is a term that describes software for anything from Internet browsers, media players, e-mail to instant messaging programs. Microsoft has provided significant information related to the complaint, Justice said at the hearing.
Other companies have complained in the past about Microsoft's post-settlement business practices. In October 2005, after an unidentified rival complained, Microsoft backed down from a plan to tie its Windows Media Player software to digital music players that compete with Apple Inc.'s iPod.