andrei@andrei-desktop:~$ sudo apt install nvidia-352-updates
Reading package lists... Done
Building dependency tree       
Reading state information... Done
nvidia-352-updates is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
1 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 nvidia-352-updates (352.63-0ubuntu0.15.10.1) ...
INFO:Enable nvidia-352-updates
DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/lenovo_thinkpad
DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/put_your_quirks_here
DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/dell_latitude
Adding system user `nvidia-persistenced' (UID 123) ...
Adding new user `nvidia-persistenced' (UID 123) with group `nvidia-persistenced' ...
useradd: existing lock file /etc/shadow.lock without a PID
useradd: cannot lock /etc/shadow; try again later.
adduser: `/usr/sbin/useradd -d / -g nvidia-persistenced -s /sbin/nologin -u 123 nvidia-persistenced' returned error code 1. Exiting.
dpkg: error processing package nvidia-352-updates (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 nvidia-352-updates
E: Sub-process /usr/bin/dpkg returned an error code (1)