An anti-malware system that reduces the likelihood of detecting a false positive. The system is applied in an enterprise network in which a server receives reports of suspected malware from multiple hosts. Files on hosts suspected of containing malware are compared to control versions of those files. A match between a suspected file and a control version is used as an indication that the malware report is a false positive. Such an indication may be used in conjunction with other information, such as whether other hosts similarly report suspect files that match control versions or whether the malware report is generated by a recently changed component of the anti-malware system.