Symantec's trade secret lawsuit against Microsoft is a sign of heightened competition between the two companies, but it's not a declaration of war, analysts said.

Last week, Symantec sued Microsoft, accusing it of misappropriating intellectual property related to data storage technology. It is the first time that the Cupertino, Calif.-based security specialist and the software giant have been on opposite sides in a legal case. In the past, the companies have teamed up to take software pirates to court.

Symantec is asking a court to bar Microsoft from further developing, selling or distributing software, including Windows Vista and Windows Server "Longhorn," until all of Symantec's intellectual property is removed. Microsoft has described Vista as one of the most important Windows releases in its history.

Symantec CEO John Thompson has repeatedly said his company won't compete by going to court or complaining to antitrust regulators. Thompson said it would instead rely on its security wits and reputation to beat Microsoft. "That hasn't changed, said Michael Cherry, an analyst at research firm Directions on Microsoft. The lawsuit is over a contract dispute that Symantec inherited when it acquired Veritas Software, he noted. "Symantec owes it to its shareholders to vigorously protect its intellectual property. I don't think there is a wider significance to this," Cherry said.

The complaint involves Symantec's Volume Manager product, which allows operating systems to store and manipulate large amounts of data. Microsoft licensed a "light" version of Volume Manager from Veritas in 1996. In its lawsuit, Symantec accuses Microsoft of violating the license.

The analysts agreed that Symantec would not have brought this action if it had not felt sure that it had a case and there was no other way to resolve the dispute. "I don't believe Symantec is the type of company that tries to compete via litigation," Gartner analyst John Pescatore said.

Microsoft CEO Steve Ballmer doesn't expect Symantec's lawsuit to delay Vista, a next version of its Windows operating system. Asked whether the case would have any effect on the Vista launch, Ballmer told Reuters: "I wouldn't anticipate any, but that will go to the courts now." Ballmer, speaking in Beijing after a news conference, did not elaborate.

But in response to another question about Vista's delay, Ballmer said: "Ultimately, I am the CEO. I am accountable." Vista, Office 2007 and Xbox 360 are central to Microsoft's efforts to revive a stock that has underperformed every major index since the beginning of 2002.