FortiClient includes an antivirus (AV) component to scan system files, executable files, removable media, dynamic-link library (DLL) files, and drivers. FortiClient also scans for and removes rootkits. In FortiClient, file-based malware, malicious websites, phishing, and spam URL protection are part of the AV component. FortiClient's AV component supports twelve levels of nested compressed files for scanning. For compressed files, FortiClient supports a maximum file size of 1 GB for antivirus scanning. For a compressed file with a size larger than 1 GB, FortiClient will scan it after decompression.