Package: xserver-xorg Version: 1:7.7+3~deb7u1 $ xlsclients -display :0 >t Maximum number of clients reachedxlsclients: unable to open display ":0" $ I have lots and lots of windows open (including around 213 xterms) - this is not a client connection leak in some application. https://bugs.launchpad.net/xorg-server/+bug/260138 seems related. Ian.