The directories responsible for a default cPanel email account is “new” and “cur“. You can find it in /home/username/mail/cur and /home/username/mail/new. If you want to remove all the emails for the default email account follow the steps given below:

# cd /home/username/mail/cur
# rm -rf *
# /home/username/mail/new
# rm -rf *

Even though you have removed all the emails from cur and new folder, the email disk quota in cPanel won’t be changed. This is because the email disk quota is cached in the file “maildirsize“. Either remove the file “maildirsize” or just rename it.

That’s it!!
Done!!!