UPDATE: A spokesperson for Microsoft Thursday evening characterized as "grossly inaccurate" reports from earlier in the day, including from Reuters, stating that a technical glitch in the company's Live Meeting services led to a dissolution of a meeting between Microsoft and security products vendors. Read the full story here.

Though officials from Microsoft had planned to hold an online briefing with representatives of security vendors, reportedly including McAfee and Symantec, earlier this afternoon, some of those participants were inadvertently shut out of the meeting. The cause, apparently, was technical difficulties with Microsoft's Live Meeting.

According to reports from Reuters, a meeting of some kind did take place, although those who were shut out of that meeting were informed by Microsoft that it would give the service another go at 5:00pm this afternoon, presumably Pacific time.

The purpose of the meeting is to enable Microsoft to respond privately to complaints raised by Symantec, and recently echoed by McAfee, that the PatchGuard kernel security feature included 64-bit versions of Windows Vista will lock out security vendors from continuing to provide their current suite of anti-malware services for Windows.

According to some reports, Microsoft may be planning to either release or develop an API that could enable vendors authenticated access to the 64-bit kernel, while continuing to lock out all other access. The company told BetaNews Wednesday that any possible changes would come after the launch of Windows Vista.

Yesterday, Gartner analyst Neil MacDonald disputed this news, saying Microsoft will instead work with a number of different independent vendors -- not just specifically these two -- to work out a more comprehensive set of APIs, which could involve sophisticated new authentication and filtering. Such a system, however, might literally take years for Microsoft to implement, suggesting it might not be available until a future service pack release of Vista.

In the meantime, MacDonald suggested that vendors instead recognize the positive benefits of Microsoft's architectural changes, and simply change their plans.

"Accept that stronger protection of the kernel is a good thing," MacDonald stated yesterday. "It is time to collaborate meaningfully on mutually agreeable mechanisms for extending kernel functionality in a controlled way and in a specific time frame that helps customers."

Microsoft is apparently withholding further comment until later this afternoon, when it will evidently have rebooted some of its Live Meeting systems.