Mail folder & settings

[Toulon7559]

Several Raspberries in use, all with Domoticz version > 2020.2.
In Setup of Domoticz all identical for Notifications and for Email (set to blanks).

Except one, all Raspberries have empty folder /var/mail, and no subfolders.
The exception (= only Raspberry type B+ in the configuration) has /var/mail with subfolders /var/mail/mail and /var/mail/pi
When opening cli with Putty, occasionally an alert that mail has arrived.

In Linux checking on mail can be done by setting a command on Putty's CLI, as explained at https://www.raspberrypi.org/forums/view ... hp?t=34172

However meanwhile /var/mail/pi filled to > 750MB, and then the checking on new mail is not anymore quick & easy.
Because no difference in Setup, puzzled why different behaviour.

2 Questions:
a) How come that only 1 Raspberry gets a (full) mail-folder?
b) How to stop that mailing, and/or how to purge that mail folder (because attributes forbid direct access)?