Microsoft released the final version of its Windows Defender antispyware tool on Tuesday, while security rivals squabbled about whether the company has given them sufficient access to Windows Vista to build competing products.The release of the final version suggests that Microsoft thinks Windows Defender is sufficiently stable and bug-free for mainstream use. The final release fixes about 400 bugs in beta 2 of the product, which was released in February. Beta versions of the program were downloaded 34 million times, a Microsoft spokeswoman said.Along with the bug fixes, customers using Windows XP and Windows 2003 get two free support calls for Windows Defender. The product is no longer supported for Windows 2000 users, since support for that OS ended in June, Microsoft said.The software is available free of charge here. It\u2019s in English now, with German, Japanese and other languages to follow shortly. It competes with free tools from Lavasoft, Spybot (Safer Networking) and others.Windows Defender is also included with Microsoft\u2019s new antivirus product, Windows OneCare, which went on sale in June for US$49.95 per year.Security vendors have been riled by Microsoft\u2019s entry into their market. McAfee and Symantec say they are being locked out of the 64-bit version of Vista by a kernel-level security feature in the OS called PatchGuard. Microsoft has dragged its feet in providing access to the kernel, they complain, which could prevent them from fully protecting their customers. Security vendor Sophos used the dispute to take a shot at its rivals. It said it has all the information about Vista that it needs, and accused Symantec and McAfee of not having designed their products with 64-bit Vista in mind."We\u2019ve taken a different approach, by focusing on catching bad behavior before it has a chance to occur," Sophos said in a statement. "Additionally, we are building our technology by making use of supported Microsoft interfaces rather than by trying to subvert them. That\u2019s why we\u2019re ready for 64-bit Vista, and others aren\u2019t." Sandi Hardmeier, a Microsoft security expert who runs the blog Spyware Sucks, was sympathetic with Sophos\u2019 position."I\u2019ve got to agree with this; if McAfee and Symantec did a little more coding and a little less bitching, they might get somewhere," she wrote in her blog.Hardmeier has argued that McAfee and Symantec should change the way they code their products instead of relying on access to the Vista kernel. Only by coming up with a new design for antivirus software will any security vendor be able to fully protect its customers, she says.On Tuesday, McAfee shot back. If Sophos doesn\u2019t need access to Microsoft\u2019s kernel, it\u2019s because it offers a less sophisticated range of products, it said."Single-product vendors, like Sophos, may well not have an issue with Microsoft. However, for an innovative security risk management vendor like McAfee, that offers its customers comprehensive security protection, full and unfettered access to the kernel is vital if we are to protect users," McAfee said.Sophos responded that McAfee is out of touch with its products.Microsoft, needless to say, seemed to enjoy the bickering."Okay, we all recognize this as a marketing move. But, hey, it\u2019s a marketing move I can smile about," Jeff Jones, a strategy director with Microsoft\u2019s security technology unit, wrote in his blog.He went on to argue that Sophos may indeed have an innovative approach to host improvement prevention systems.-James Niccolai, IDG News Service (Paris Bureau)Related Links:\n\nMicrosoft Hits Back at McAfee Criticism\n\nMcAfee: Microsoft Not Keeping Security Promises\n\nMicrosoft Vista Security Talks off to Bad Start\n\nRivals: Microsoft Locking Others Out of Vista SecurityThis article is posted on our Microsoft Informer page.\u00a0For more news on the Redmond, Wash.-based powerhouse, keep checking in.Check out our CIO News Alerts and Tech Informer pages for more updated news coverage.