Only one security vendor is shipping a final version of security applications for Windows Vista on the day the operating system became available for large businesses.

McAfee launched its VirusScan 8.5 and AntiSpyware 8.5 on Thursday, the same day that Microsoft officially launched its operating system to businesses with volume licensing at events around the world.

The applications promise to protect both 32-bit and 64-bit versions of Vista. This is despite concerns over the Patchguard technology that Microsoft has built into the 64-bit version of the application, which prevents certain security technologies from functioning properly.

Most security suites for the operating system are still in beta, but are slated for availability as final products in time for Windows Vista's 30 January consumer launch.

Symantec, for instance, earlier this week made available beta or test versions of its Norton Internet Security 2007 and Norton AntiVirus 2007 products. Both target consumer PCs. Its enterprise-class offerings have also not yet been launched.

"McAfee is the only major security vendor with products available today that support Vista right out of the gate," boasted Rees Johnson, McAfee's president of product management.

The limited availability of security software, however, is unlikely to have a big impact on Vista deployments with enterprises. Companies are expected to take at least one year to evaluate the new operating system before they roll it out on production systems.

Among other things, they need to test internally-developed and third-party applications for potential compatibility issues.