This is a small service program but had been confused me for a whole day. Originally I removed this service. Later I found my cd or usb disk can’t be automatically mounted giving complains like “org.desktop.hal permission denied” whenever the disk was pluged or inserted. Finally service “consolekit” was found responsible for that. When you stop this service, you got the above complain. By only restarting this service simply seemed not solving the problem. Only after restarting the computer with this service on, you get through. Trick!