"Robin S. Socha" <robin@socha.net> writes:

> * ShengHuo ZHU <zsh@cs.rochester.edu> writes:
> > You can redefine or advise display-time-file-nonempty-p to check
> > maildir.
> 
> You can. I can't. Could you? Please? Thanks *a lot* in advance,

Try this and make sure display-time-mail-file or the environment
variable MAIL is set as a string (whatever it is).

(require 'mail-watch)
(setq mail-watch-files-or-directories '("/my/maildir/new"))
(display-time)

ShengHuo