mail home is set by database

templates/conf.d/10-mail.conf.j2

@@ -27,7 +27,7 @@
 #
 # <doc/wiki/MailLocation.txt>
 #
-mail_home = /var/vmail/%d/%n
+#mail_home = /var/vmail/%d/%n
 mail_location = mdbox:~/mail.mdbox
 
 # If you need to set multiple mailbox locations or want to change default