Comment 17 for bug 1401591

My output when failing:

Removing libcuda1-331 (331.113-0ubuntu0.1) ...
Removing nvidia-331-uvm (331.113-0ubuntu0.1) ...
Removing all DKMS Modules
Done.
Removing nvidia-331 (331.113-0ubuntu0.1) ...
Removing all DKMS Modules
Done.
update-alternatives: using /usr/lib/nvidia-331-prime/ld.so.conf to provide /etc/ld.so.conf.d/x86_64-linux-gnu_GL.conf (x86_64-linux-gnu_gl_conf) in auto mode
update-alternatives: using /usr/lib/nvidia-331-prime/alt_ld.so.conf to provide /etc/ld.so.conf.d/i386-linux-gnu_GL.conf (i386-linux-gnu_gl_conf) in auto mode
update-alternatives: using /usr/lib/x86_64-linux-gnu/mesa/ld.so.conf to provide /etc/ld.so.conf.d/x86_64-linux-gnu_GL.conf (x86_64-linux-gnu_gl_conf) in auto mode
update-alternatives: using /usr/lib/i386-linux-gnu/mesa/ld.so.conf to provide /etc/ld.so.conf.d/i386-linux-gnu_GL.conf (i386-linux-gnu_gl_conf) in auto mode
INFO:Disable nvidia-331
DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/put_your_quirks_here
DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/dell_latitude
DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/lenovo_thinkpad
stop: Unknown job: nvidia-persistenced
userdel: user nvidia-persistenced is currently used by process 4117
dpkg: error processing package nvidia-331 (--remove):
 subprocess installed post-removal script returned error exit status 8
Removing nvidia-opencl-icd-331 (331.113-0ubuntu0.1) ...
Processing triggers for libc-bin (2.19-10ubuntu2.2) ...
Processing triggers for man-db (2.7.0.2-2) ...
Errors were encountered while processing:
 nvidia-331
E: Sub-process /usr/bin/dpkg returned an error code (1)

It seems the error occurs while doing some changes on the user "nvidia-persistenced", that is used by the process 4117 (nvidia-persiste)
I got the name of the process with:

# sudo ps -e | grep nvidia
=> 4117 ? 00:00:00 nvidia-persiste

And killed it:
# sudo kill 4117

Then could install with no issues and the output shows the operation on the user "nvidia-persistenced" is now successful:

Removing nvidia-331 (331.113-0ubuntu0.1) ...
stop: Unknown job: nvidia-persistenced
update-initramfs: deferring update (trigger activated)
Processing triggers for initramfs-tools (0.103ubuntu8) ...
update-initramfs: Generating /boot/initrd.img-3.16.0-30-generic
Processing triggers for libc-bin (2.19-10ubuntu2.2) ...
Selecting previously unselected package libcuda1-331-updates.
(Reading database ... 358904 files and directories currently installed.)
Preparing to unpack .../libcuda1-331-updates_331.113-0ubuntu0.1_amd64.deb ...
Unpacking libcuda1-331-updates (331.113-0ubuntu0.1) ...
Selecting previously unselected package nvidia-331-updates.
Preparing to unpack .../nvidia-331-updates_331.113-0ubuntu0.1_amd64.deb ...
Unpacking nvidia-331-updates (331.113-0ubuntu0.1) ...
Selecting previously unselected package nvidia-331-updates-uvm.
Preparing to unpack .../nvidia-331-updates-uvm_331.113-0ubuntu0.1_amd64.deb ...
Unpacking nvidia-331-updates-uvm (331.113-0ubuntu0.1) ...
Selecting previously unselected package nvidia-opencl-icd-331-updates.
Preparing to unpack .../nvidia-opencl-icd-331-updates_331.113-0ubuntu0.1_amd64.deb ...
Unpacking nvidia-opencl-icd-331-updates (331.113-0ubuntu0.1) ...
Processing triggers for man-db (2.7.0.2-2) ...
Processing triggers for ureadahead (0.100.0-16) ...
Setting up libcuda1-331-updates (331.113-0ubuntu0.1) ...
Setting up nvidia-331-updates (331.113-0ubuntu0.1) ...
update-alternatives: using /usr/lib/nvidia-331-updates/ld.so.conf to provide /etc/ld.so.conf.d/x86_64-linux-gnu_GL.conf (x86_64-linux-gnu_gl_conf) in auto mode
update-alternatives: using /usr/lib/nvidia-331-updates/alt_ld.so.conf to provide /etc/ld.so.conf.d/i386-linux-gnu_GL.conf (i386-linux-gnu_gl_conf) in auto mode
update-alternatives: using /usr/share/nvidia-331-updates/glamor.conf to provide /usr/share/X11/xorg.conf.d/glamoregl.conf (glamor_conf) in auto mode
update-initramfs: deferring update (trigger activated)
INFO:Enable nvidia-331-updates
DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/put_your_quirks_here
DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/dell_latitude
DEBUG:Parsing /usr/share/ubuntu-drivers-common/quirks/lenovo_thinkpad
Adding system user `nvidia-persistenced' (UID 128) ...
Adding new group `nvidia-persistenced' (GID 138) ...
Adding new user `nvidia-persistenced' (UID 128) with group `nvidia-persistenced' ...
Not creating home directory `/'.
Loading new nvidia-331-updates-331.113 DKMS files...
First Installation: checking all kernels...
Building only for 3.16.0-30-generic
Building for architecture x86_64
Building initial module for 3.16.0-30-generic
Done.

nvidia_331_updates:
Running module version sanity check.
 - Original module
   - No original module exists within this kernel
 - Installation
   - Installing to /lib/modules/3.16.0-30-generic/updates/dkms/

depmod....

DKMS: install completed.
Setting up nvidia-331-updates-uvm (331.113-0ubuntu0.1) ...
Loading new nvidia-331-updates-uvm-331.113 DKMS files...
First Installation: checking all kernels...
Building only for 3.16.0-30-generic
Building for architecture x86_64
Building initial module for 3.16.0-30-generic
Done.

nvidia-331-updates-uvm:
Running module version sanity check.
 - Original module
   - No original module exists within this kernel
 - Installation
   - Installing to /lib/modules/3.16.0-30-generic/updates/dkms/

depmod....

DKMS: install completed.
Setting up nvidia-opencl-icd-331-updates (331.113-0ubuntu0.1) ...
Processing triggers for libc-bin (2.19-10ubuntu2.2) ...
Processing triggers for initramfs-tools (0.103ubuntu8) ...
update-initramfs: Generating /boot/initrd.img-3.16.0-30-generic