Free antivirus software

ClamAV (Clam AntiVirus) is a free software, cross-platform antimalware toolkit able to detect many types of malware, including viruses. It was developed for Unix and has third party versions available for AIX, BSD, HP-UX, Linux, macOS, OpenVMS, OSF (Tru64), Solaris and Haiku. As of version 0.97.5, ClamAV builds and runs on Microsoft Windows. Both ClamAV and its updates are made available free of charge. One of its main uses is on mail servers as a server-side email virus scanner.

free and open-source antivirus tool for Windows

ClamTk is a free and open-source graphical interface for the ClamAV command-line antivirus software program for Linux desktop users. It provides both on-demand and scheduled scanning. The project was started by Dave Mauroni in February 2004. As of April 2024, the program is no longer maintained.