If you installed from source

• ./configure
• sudo make uninstall

If you installed from packages

• Debian: dpkg --remove clamav*
• Ubuntu: sudo apt-get purge clamav clamav-base clamav-daemon clamav-freshclam libclamav6
• Redhat/Fedora: yum remove clamav*
• Mandriva: urpme clamav
• Gentoo: emerge -C clamav
• FreeBSD: pkg_deinstall -f security/clamav*
• Slackware: /etc/rc.d/rc.clamav stop; removepkg clamav

Caveats

Make sure that you haven’t got old libraries (libclamav.so) lying around your filesystem. You can verify it using: $ ldd `which freshclam`

Also make sure there is really only one version of ClamAV installed on your system:

$ whereis freshclam

$ whereis clamscan

-- LucaGibelli - 15 Nov 2006