Businesses should not rely on Microsoft's future operating system to secure desktops against viruses, analyst Gartner Group has warned, despite its plans to embed the recently acquired GeCAD antivirus engine into Windows.

Gartner predicted that by 2008 it is likely that 80 per cent of companies will be using Longhorn - the desktop release of Windows due in 2005 - for lock down and antivirus management, rather than third-party software.

However, Arabella Hallawell, research director at Gartner, warned attendees at the analyst's IT Security Summit against relying solely on Microsoft for antivirus protection at the desktop.

"A fully integrated Microsoft antivirus solution may appear attractive, but non-Windows platforms may not be supported," she said.

"XP is not good enough for the enterprise and, if companies wait for Longhorn, there are questions over how effective the new personal firewall will be."

Companies that neglect the desktop, believing gateway and email servers to be prime detection points for viruses, are also misguided, according to the analyst.

"With things like instant messaging, protecting the desktop is still very important," she said.

Hallawell advised companies with many end users with broadband access to at least consider "a tactical rollout" of antivirus desktop protection.

But the Microsoft threat to antivirus vendors at the desktop could prove beneficial to users.

"Antivirus vendors will be on the defensive over the next two or three years, so must strive to provide more value to customers such as more remote access support," explained Hallawell.

Increased support is necessary because fighting viruses is the security priority for businesses.

"Organisations are still finding that virus management is the number one security pain point," said the analyst.

"It can cost a business between £10,000 and £300,000 just to clean up after a virus attack, which does not begin to cover productivity costs if email and web servers are down."

Hallawell warned against relying on signature-based antivirus protection that checks for viruses using databases at the desktop.

"It is not enough, especially during initial outbreaks. Companies should look at blocking and patch management," she said.

"They should conduct negotiations with antivirus vendors under the assumption that signature-based antivirus at the desktop is a legacy technology."