First let me make sure I'm looking at the right file: /etc/X11/Xsession.d/55numlockx /etc/X11/Xsession.d/55numlockx.dpkg-dist The first one is the currently installed version right? It contains: ( test -x /usr/bin/X11/numlockx && /usr/bin/X11/numlockx on ) but the numlockx package has its executable here: /usr/bin/numlockx