QMail mailserver is installed on the server. Directory
/usr/local/psa/handlers/spoolis constantly filled up with mail messages which are not removed automatically, but they are supposed to.
Plesk mchk (
/usr/local/psa/admin/sbin/mchk) utility does not help.
Software issue #PPPM-1766 was confirmed and was fixed in microupdate #8 for Plesk 12: 12.0.18 MU#8
If update is not possible in your case you could use one of following workarounds:
/var/qmail/bin/qmail-queuewith custom fix (attached)
Switch from QMail to Postfix
Create a cron task to clean up spool directory periodically.