LinuxQuestions.org - Gnome 3.6 Black screen after the last update

I've updated my systems, as usual both of my systems laptop and desktop.first laptop cant start gnome 3.6, it works by adding the initrd to the kernel line on grub config file.But i am not lucky for the desktop,

I've performed the actions for desktop again, but it doesnt work.After that i 've decided to migrate to the pure systemd by following the descriptions on wiki page.But it doesnt work yet.System goes well to the login screen without graphical desktop.The only problem for the multi-user.target is long login action.When i log into the system, it waits for aprox. 15-20 seconds, then login successfully completes.On the other hand, when i change the graphical.target with "systemctl isolate graphical.target" it starts the X, but only i can see is "black screen" with a clock mouse pointer.

Finally I've found the clue to fix it while searching the net on the following link

https://bbs.archlinux.org/viewtopic.php?pid=1187469

I've realized that polkit.service is not runnning for me too.I havent "polkitd" group.Then i've added the polkitd with 102 GID number to my /etc/group file but nothing changed and searched again /etc/group file for gdm.Yeah i got it all, the GDM group has the same gid,which is 102, with the polkitd.Then 'Ive removed the polkitd group from the /etc/group file, unistalled the gdm and polkit, then reinstalled gdm and checked the /etc/group file.It has 120 GID number, then reinstalled the polkit package, checked again the file.The polkit has 102 GID number.

After all when i reboot the system there is no waiting period for multi-user.target as i mentioned before.Then enable the graphical.target with the command

systemctl enable graphical.target

everything is fine now.I guess this is the SOLVED topic now