Thank you Bastien: you were right: one of my previous settings was the
problem: the use as the default font of TeX Gyre Termes which so far I had
not yet installed on this computer with Mountain Lion.
Sorry for asking for help because of this stupid mistake.

So far I find only this other problem in using Org Mode on Mountain Lion:
on the previous computer with Lion when using Org mode I was able to
display in a buffer a .png image when I clicked on an hyperlink in an Org
mode file which pointed to this type of file.

Now If I do the same this message is displayed:

Cannot display image: (Cannot determine image type)

(by the way: the hyperlink to the file is correct and in fact when I export
the Org file to LibreOffice the .png image is rightly displayed).

In my Emacs settings the option Image File Name Extensions
contains a list of extensions among which the .png

and Auto Image File Mode is set on

So any idea what is the right configuration for displaying in a buffer a
.png image when using Org mode?

Pierfranco

2012/8/24 Bastien <bzg@altern.org>

> Hi Pierfranco,
>
> Pierfranco Minsenti <pierfranco.minsenti@gmail.com> writes:
>
> > What should I do to check which version of Emacs is charged when I
> > use the Terminal application?
>
> M-x emacs-version RET
> M-x org-version RET
>
> I'm not a Mac user, but I'm pretty sure ~$ emacs from the Terminal
> is *not* linked to the Aquamacs executable.
>
> I don't know what is the equivalent to "~$ emacs -Q" for launching
> a bare Aquamacs instance, but maybe for now just remove any .emacs.el
> and see if the problem comes from your configuration?
>
> --
>  Bastien
>