Microsoft has endowed Vista's kernel with highly restricted access, in a bid to improve security in its new operating system. This extra security has succeeded in locking out hackers, malware purveyors and has apparently locked out security software as well.
Competing security software manufacturers say Vista's security system alone is not enough to protect users from threats. Security firm, Webroot Software reported in January that its security testing of Vista revealed significant holes in its security shields. The tests showed Vista to have ineffective blocking capabilities and weak antivirus capabilities in the default anti-spyware and antivirus components within Vista. Webroot also found problems in Microsoft's Live OneCare security suite.
Webroot said Windows Defender failed to block 84 percent of a testing sample set that included 15 of the most common variations of existing spyware and malware. On top of this, Windows Defender did not perform at the level of many third-party security applications.