I have a F23 server with minimal working X (no desktop). All was working well with kernel-4.2.x With kernel-4.3.x I get (in xterm): [a53@s ~]$ su -c virt-manager Password: [a53@s ~]$ No protocol specified Unable to init server: Could not connect: Connection refused (virt-manager:54862): Gtk-CRITICAL **: gtk_settings_get_for_screen: assertion 'GDK_IS_SCREEN (screen)' failed [a53@s ~]$ journalctl gives: kernel: virt-manager[8896]: segfault at 0 ip 00007f612fce78a9 sp 00007ffe5a45e580 error 4 in libgtk-3.so.0.1800.6[7f612fa2d000+710000] kernel: BUG: unable to handle kernel NULL pointer dereference at 0000000000000060 Searching the web I discovered that during years this error shows up from time to time across different distributions (including Fedora). This time it seems to be kernel related and does not show up with Gnome. C.S -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines Have a question? Ask away: http://ask.fedoraproject.org