Enabling ClamAV in Plesk Email Security fails: Cannot allocate memory

Taras Ermoshin

Updated January 13, 2026 19:07

Plesk for Linux kb: technical ext: pes

Applicable to:

Plesk for Linux

Symptoms

Enabling ClamAV in the Plesk Email Security extension fails:

PLESK_ERROR: Execution filemng has failed with exit code 1, stdout: , stderr: Job for clamd@scan.service failed because the control process exited with error code. See "systemctl status clamd@scan.service" and "journalctl -xe" for details.
Manually enabling the service clamd in the server's console also fails:

# systemctl status clamd@scan.service
* clamd@scan.service - clamd scanner (scan) daemon
Loaded: loaded (/usr/lib/systemd/system/clamd@.service; enabled; vendor preset: disabled)
Active: activating (start)
...
clamd[17834]: daemonize() failed: Cannot allocate memory
clamd[17834]: Socket file removed.

Clamd process has a high CPU usage:

# ps awufx | grep clamd | grep -v grep
amavis 1804892 96.3 24.7 1117096 968048 ? Rs 17:19 0:10 /usr/sbin/clamd -c /etc/clamd.d/amavisd.conf
The following error is shown multiple times on the /var/log/maillog file:

# egrep "Cannot allocate memory" /var/log/maillog | wc -l
3114

Cause

There is not enough RAM memory to initialize the service. The server should have at least 4 GB of overall RAM and 2 GB free RAM.

Resolution

Allocate more RAM to the server either on your own or by contacting the administrator/provider of the server.

Additional Information

The clamav-milter service, which is a part of Plesk Email Security extension, is stopped by default. The service is managed by Clam Antivirus and is started automatically on a request.