"Elements of the security software will still work, but Patchguard will prevent all of them from functioning," a company said.
The Symantec betas, however, target consumers. Patchguard is a limited issue for the consumer segment because the vast majority of such users are expected to run the 32-bit version of the operating system.
Security vendors including McAfee and Symantec have been pressing Microsoft to cooperate and have lobbied the European Commission and Korean government to force the Redmond firm to open up its kernel.
The PatchGuard technology blocks access to the Vista kernel, blocking security technologies that rely on behavioural profiling as well as anti-tampering features that verify a system is running anti-virus software and a firewall.
While Microsoft has promised to make changes to its technologies, Gartner has suggested that these could take until 2008 before they are fully implemented.
The beta is available from Symantec's website.