mspools-vm-system-mail

mspools-vm-system-mail is a variable defined in `mspools.el'.
Its value is

"/var/spool/mail/artur"

Documentation:
Spool file for main mailbox. Only used by VM.
This needs to be set to your primary mail spool - mspools will not run
without it. By default this will be set to the environment variable
$MAIL. Otherwise it will use `rmail-spool-directory' to guess where
your primary spool is. If this fails, set it to something like
/usr/spool/mail/login-name.

You can customize this variable.