Recipe:

% cd ~
% touch foo
% emacs -Q
M-x write-file
Write file: ~/foo

Then nothing is displayed in the minibuffer, but any trigger
(a keystroke or a mouse event) makes it appear.

In GNU Emacs 25.0.50.1 (i686-pc-cygwin, GTK+ Version 3.10.9)
 of 2015-09-03
Windowing system distributor 'The Cygwin/X Project', version 11.0.11501000
Configured using:
 'configure --verbose --with-x-toolkit=gtk3'