All AVs update their definitions and detection methods daily, sometimes 2, 3, more, times a day (at least all the good ones do). And occasionally mistakes get made and things get blacklisted that shouldn't be. I'm not familiar with SecureAnywhere, but this is their webpage about checking what it has quarantined: https://www.webroot.com/En_US/SecureAnywhere/PC/Content/C5_Quarantine/CH5a_ManagingQuarantine.htm If you do find that it has quarantined CCleaner then you should restore it,