ClamAV needs to be installed on the Nextcloud host for the Nextcloud’s Antivirus App to work. I am using TurnKey Linux (TKL) Nextcloud and TKL based image is Debian. To install ClamAV
apt install -y clamav clamav-daemon
After installing the ClamAV, go back to the Nextcloud App Store search and download and enable the app Antivirus for files. The setting for this app can be found in the Settings > Administration > Security > Antivirus for Files as shown in Figure 1.
That’s about it. This is one of the easiest app to install. Hope you’ll find this helpful.