1.Go to /home/cPanel user/mail/domain.com/emailaccount/
[root@vps root]# cd /home/cPaneluser/mail/domain.com/emailaccount/
[root@vps root]# ls
2.Delete file named maildirsize, this file stores disk usage information.
[root@vps root]# rm maildirsize
rm: remove regular empty file 'maildirsize'? y
3.Change the number of disk quota for that email account from WHM /cPanel, it will regenerate a new maildirsize file.
WHM >> Main >> Account Information >> List Accounts >> Select Domain >> cPanel >> Mail >> Email Accounts >> Mailbox Quota.
Refresh your browser and now you should see the correct disk quota for that email account.
