1. Login to Plesk Panel.
2. Click on "Domains" under "Hosting services".
3. Select the domain for which you need to recalculate the actual disk space used by mailboxes.
4. Click on "Mail" tab.
5. Select the email account and click "Refresh Usage Stats".
Note: If the plesk panel still shows inaccurate usage for the email account, you may please get contact ByteHouse Technical Support so that we can fix the issue.