[@Charles] ALL antivirus programs are retrospective in their detection, without a malicious already being out there in the live piece of malware it cannot be examined and a suitable pattern generated to match it… to try and counter that anti-malware software uses heuristics to try and predict in the absence of evidence the chances an executable might be malicious but rarely presents the reasons behind its accusations. NO anti-malware software or hardware can prove ANY software is 100% clean or safe.