Among the additions coming to Windows 8 should be an Apple-like file checking system that would refuse to run files known or suspected to be rogue. Microsoft's SmartScreen, a system first found in Internet Explorer and Windows Live Messenger, will check files for whether they're malware or otherwise illegal and could stop them from running. The method would prevent 'social' viruses, where users end up bypassing their usual safeguards because they think it comes from a known source.
The implementation would be more complex than what Apple offers in Mac OS X, where the checks are based on sporadically updated malware signature lists. SmartScreen could be based on some algorithmically generated information to more aggressively update the list. Windows users would have the option of fine-tuning settings and could either go from turning SmartScreen off altogether to refusing to open any file that didn't clear the SmartScreen check.
Windows 8 is due to be completed and shipping by late 2012 but could be in beta by September this year.
(full article at Windows 8's SmartScreen to build on Apple's file screening (Electronista)