ClamAV Antivirus error in Plesk: Failed to start clamd@scan.service: Unit not found.

Symptoms

• Unable to install ClamAV via Extensions > Plesk Email Security:

  Execution filemng has failed with exit code 1, stdout: , stderr: Failed to execute operation: No such file or directory

• If ClamAV is already installed it cannot be started via Extensions > Plesk Email Security with the following error:

  Execution filemng has failed with exit code 5, stdout: , stderr: Failed to start clamd@scan.service: Unit not found.

Cause

Incorrect ClamAV packages are installed when the Atomic repository is enabled on the server:

# yum repolist enabled | grep atomic
*atomic: www4.atomicorp.com
atomic/7/x86_64 CentOS / Red Hat Enterprise Linux 7 - atomic 930

Resolution

1. Log in to Plesk.

2. Remove Plesk Email Security extension via Extensions > Plesk Email Security > More > Remove:
   

3. Connect to the server via SSH.

4. Find all the ClamAV packages, for example:

   # rpm -qa | grep clam
   clamd-0.102.3-13765.el7.art.x86_64
   clamav-milter-debuginfo-0.104.3-25721.el8.art.x86_64
   clamav-db-0.104.3-25721.el8.art.x86_64

   And remove them using the commands below:

   # yum remove clamd-0.102.3-13765.el7.art.x86_64
   # yum remove clamav-milter-debuginfo-0.104.3-25721.el8.art.x86_64
   # yum remove clamav-db-0.104.3-25721.el8.art.x86_64

5. Disable the Atomic repository:

   # yum-config-manager --disable atomic

6. Reinstall Plesk Email Security under Plesk > Extensions > Plesk Email Security > Get it Free:
   

7. Go to Extensions > Plesk Email Security and install all the required components again along with ClamAV.