Thanks Dmitry for the help. The --reconfigure option is unknown by dpkg. Tried with --configure but I get the same error message. Before reading your solution, I've tried to remove from synaptic the lightdm package along with xubuntu-desktop packages that depends on it.
Now the error I got is this:Reading package lists... Done Building dependency tree Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 3 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Do you want to continue [Y/n]? y Setting up lightdm-gtk-greeter (1.0.1-0ubuntu6) ... update-alternatives: error: alternative path /etc/lightdm/lightdm-gtk-greeter-ubuntu.conf doesn't exist. dpkg: error processing lightdm-gtk-greeter (--configure): subprocess installed post-installation script returned error exit status 2 No apport report written because MaxReports is reached already dpkg: dependency problems prevent configuration of xubuntu-default-settings: xubuntu-default-settings depends on lightdm-gtk-greeter (>= 1.0.0-0ubuntu2); however: Package lightdm-gtk-greeter is not configured yet. dpkg: error processing xubuntu-default-settings (--configure): dependency problems - leaving unconfigured No apport report written because MaxReports is reached already dpkg: dependency problems prevent configuration of xubuntu-desktop: xubuntu-desktop depends on lightdm-gtk-greeter; however: Package lightdm-gtk-greeter is not configured yet. xubuntu-desktop depends on xubuntu-default-settings; however: Package xubuntu-default-settings is not configured yet. dpkg: error processing xubuntu-desktop (--configure): dependency problems - leaving unconfigured No apport report written because MaxReports is reached already Errors were encountered while processing: lightdm-gtk-greeter xubuntu-default-settings xubuntu-desktop E: Sub-process /usr/bin/dpkg returned an error code (1) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/868176 Title: package lightdm-gtk-greeter 1.0.1-0ubuntu1 failed to install/upgrade: lightdm-gtk-greeter: config file '/etc/lightdm/lightdm-gtk-greeter- ubuntu.conf' is a circular link To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/868176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs