In some cases there could be damaged AV signatures and ClamAV does not run properly. This can be fixed in the linux console by running "ft av_update", this will re-download and re-build all AV stuff from scratch. During ft av_update, please select to remove existing av signatures. After then try to restart ClamAV by typing "systemctl restart clamd". Finally run "ft avscan_all_files" to rescan all files. This procedure takes a while.
