$ls -l /usr/local/bin/gs*  You should see a line lrwxr-xr-x 1 root wheel 8 Oct 3 07:53 /usr/local/bin/gs@ -> gs-X11  If so, then do this: $ sudo bash
$cd /usr/local/bin$ rm gs
$ln -s gs-noX11 gs$ exit

(You may have installed Mac TeX when you had X11 installed, in which case the program "gs" was created as a link pointing to /usr/local/bin/gs-X11. The point is to change it so it points to /usr/local/bin/gs-noX11 instead, since when you upgraded the OS, X11 was removed.)