The range of security software in Microsoft's forthcoming Windows Vista operating system could cause some security firms to go to the wall, according to a new report from Yankee Group.

First for the chop will be anti-spyware and desktop firewall vendors, since both functions are now built into Vista.

But although Vista will have little or no effect on the corporate antivirus sector, Yankee Group expects that the market shares of existing competitors will decrease slightly following the introduction of Microsoft's own antivirus offerings.

"Windows Vista will bring spectacular improvements to the overall level of security for users, but only if Microsoft succeeds in making customers and ISVs comfortable with the new security system," said Andrew Jaquith, security solutions and services programme manager at Yankee Group.

"However, Windows security issues will continue to be a permanent fact of life for Microsoft, which means that third parties will always have a rich and robust aftermarket available to serve."

The analyst firm's report does, however, have bad news for Microsoft. It estimates that take up of the new operating system will be slower than Microsoft's estimate of 400 million desktops in 24 months.

Yankee Group also expects that many customers will defer major upgrades because of the expense of upgrading end-user desktops, and because Microsoft will market security as a "feature" for which users must pay.