This bug pertains to the following section of code within the startxfce4 script of xfce-utils 4.6.0: if test "x$XDG_DATA_DIRS" = "x" then XDG_DATA_DIRS="/usr/local/share:/usr/share:/usr/share" else XDG_DATA_DIRS="$XDG_DATA_DIRS:/usr/share" fi export XDG_DATA_DIRS The problem is /usr/share is appended to the environment variable twice, causing problems with some applications such as lxappearance.