The Redmond, Wash.-based software giant filed a motion with the U.S. Court for the Western District of Washington against Lindows, which is developing a version of the Linux operating system that will run popular applications written for Microsoft's Windows OS.
Microsoft contends the company, which plans to formally release its product next year, purposely is trying to confuse Lindows with Windows. The suit asks the court to order the start-up to stop using the Lindows name and also seeks unspecified monetary damages.
"We're not asking the court to stop the company from making their products," said Microsoft spokesman Jon Murchinson. "What we're saying is they should not use a name that could confuse the public and infringe on our valuable trademark."
Lindows is based on the Wine project, an open-source effort to mimic the commands that Windows programs use. The San Diego-based Lindows company was launched earlier this year by Michael Robertson, former CEO of digital music site MP3.com.
Robertson characterized the move as another attempt by Microsoft to thwart a viable threat to its Windows empire.
"If they're alleging that people are going to be confusing Microsoft Corp. with Lindows.com, I think there's zero potential of that happening," he said. "If people are confused, just remember that we're not the convicted monopolist."
Murchinson said Microsoft considered legal action a last resort.
"Clearly we prefer to work with them to resolve this problem voluntarily. Their product name infringes on our trademark," Murchinson said. "We hope they will work with us to resolve this problem without the need for legal action."
Robertson said he had heard from nobody at Microsoft regarding the name dispute. "They just filed lawsuits," he said.
Microsoft has been involved in an increasingly fractious war of words with Linux supporters this year, with Microsoft executives castigating the open-source distribution model behind Linux as a sure road to commercial failure and on blight for software development.
Emmett Stanton, an attorney at Palo Alto, Calif.-based Fenwick & West, said Microsoft has not been overzealous in the past about protecting its trademark, allowing spoof sites and others to go unchallenged.
"They're not the type to sue at the drop of a hat," he said, concluding that there appears to be solid ground for the Lindows complaint. "Superficially, you would have to say there's some potential for confusion, and the defendant may be trying to trade on Microsoft's position in the marketplace."
Robertson said he hoped to have a preview version of Lindows ready for download by next week, with a full version ready early next year. He said the company is targeting small and medium-sized business that might be interested in switching to a less expensive operating system but have invested in Windows applications such as Office.
"We're trying to give consumers a choice, where there's really no choice today," he said.