Comment 6 for bug 1453193

running 'locale-gen' does not resolve, may be the problem comes from my 'mixed' locale (language en, keybord it)?

corrado@corrado-HP-620-U8:~$ locale
LANG=en_US.UTF-8
LANGUAGE=en_US
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC=it_IT.UTF-8
LC_TIME=it_IT.UTF-8
LC_COLLATE="en_US.UTF-8"
LC_MONETARY=it_IT.UTF-8
LC_MESSAGES="en_US.UTF-8"
LC_PAPER=it_IT.UTF-8
LC_NAME=it_IT.UTF-8
LC_ADDRESS=it_IT.UTF-8
LC_TELEPHONE=it_IT.UTF-8
LC_MEASUREMENT=it_IT.UTF-8
LC_IDENTIFICATION=it_IT.UTF-8
LC_ALL=
corrado@corrado-HP-620-U8:~$

I also rerun the command to update lxc but ...

corrado@corrado-HP-620-U8:~$ sudo unity8-lxc-setup --update-lxc
[sudo] password for corrado:
Starting the container
lxc_container: cgmanager.c: lxc_cgmanager_enter: 694 call to cgmanager_move_pid_abs_sync failed: invalid request
lxc_container: cgmanager.c: cgm_attach: 1324 Failed to enter group /lxc/unity8-lxc/system.slice/cgproxy.service
lxc_container: attach.c: lxc_attach: 831 error communicating with child process
lxc_container: cgmanager.c: lxc_cgmanager_enter: 694 call to cgmanager_move_pid_abs_sync failed: invalid request
lxc_container: cgmanager.c: cgm_attach: 1324 Failed to enter group /lxc/unity8-lxc/system.slice/cgproxy.service
lxc_container: attach.c: lxc_attach: 831 error communicating with child process
Updating packages inside the LXC...
lxc_container: cgmanager.c: lxc_cgmanager_enter: 694 call to cgmanager_move_pid_abs_sync failed: invalid request
lxc_container: cgmanager.c: cgm_attach: 1324 Failed to enter group /lxc/unity8-lxc/system.slice/cgproxy.service
lxc_container: attach.c: lxc_attach: 831 error communicating with child process
lxc_container: cgmanager.c: lxc_cgmanager_enter: 694 call to cgmanager_move_pid_abs_sync failed: invalid request
lxc_container: cgmanager.c: cgm_attach: 1324 Failed to enter group /lxc/unity8-lxc/system.slice/cgproxy.service
lxc_container: attach.c: lxc_attach: 831 error communicating with child process
corrado@corrado-HP-620-U8:~$

will try with rebuild-all

thanks.