Email Disk Usage still showing after deleting messages

Symptoms

After clearing messages from an email account using mdbox, the disk usage in /home/user/mail/domain.tld/account/ still is used.

Description

This behavior is due to how Dovecot stores and processes messages when using the mdbox storage system. The email messages are stored in databases within the user's home directory. When messages are removed, Dovecot unlinks them in the database, but the data is still stored on the disk.  This is usually triggered automatically on IMAP activity, but can be manually removed with the doveadm utility.

Workaround

1. Access the server's command line as the 'root' user via SSH or "Terminal" in WHM.
2. Run the following command.

   doveadm purge -u account@domain.tld

   Please note that "account@domain.tld" must be replaced with the email account from which to remove the data.

Additional resources

doveadm-purge