A Microsoft spokeswoman said via e-mail Thursday that the company is holding meetings to "initiate discussions with partners on the process for developing methods by which third-party software can work alongside Kernel Patch Protection on 64-bit platforms without disabling it or weakening the protections offered by it."

The company's decision appears to have been prompted by growing vendor criticism over Microsoft's delay in providing details after it had already publicly committed to releasing the APIs (http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9004228).

A spokesman for Symantec Corp., one of the vendors that has been critical of Microsoft's silence, confirmed this morning that an online meeting with Microsoft was scheduled for later Thursday to discuss PatchGuard-related APIs. A McAfee Inc. spokeswoman also confirmed that a meeting was taking place but added, "The content of the meeting remains to be seen."

A senior executive at another security vendor who requested anonymity added that the meeting was being conducted under very tight nondisclosure agreements.

PatchGuard has been at the center of a simmering dispute between Microsoft and several security vendors, most notably Symantec and McAfee. Microsoft maintains that Patch Guard would increase operating system reliability by protecting the Vista kernel from unauthorized modification by third parties, including security vendors and malicious attackers.