System Centos 7.x Dovecot ISPConfig 3.0.5.4p8 (clean perfect server...) Example e-mail: [email protected] custom login: user.example.com I get two diferent .quotausage files Every sieve action (new incoming e-mail) - creates or updates /var/vmail/example.com/user/.quotausage file with positive values increasing to infinity. Every dovecot action (mail retriving) - creates /var/vmail/user.example.com/ folder and/or updates /var/vmail/user.example.com/.quotausage file with negative valuse (after some number of retrievings) decreasing to minus-infinity. This results in false mail quota exceeding. Workaround cron.hourly rm -f /var/vmail/*/*/.quotausage Possible cause I thing this is problem in the Dovecot quota plugin. In /etc/dovecot/dovecot.conf file: plugin { quota = dict:user::file:/var/vmail/%d/%n/.quotausage ...; what mechanism regenerates (from db) %d and %n parts corresponding to custom username and passes it to the quota plugin? protocol imap { mail_plugins = quota imap_quota ...; what is imap_quota mail_plugin?