The cause may actually be due to dbus, when it is restarted. I've reported the following bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=777691 -- Vincent Lef?vre <vincent at vinc17.net> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)