Unity desktop broken after last update

[Roberto González Correa]

Few days ago, I updated my system from Ubuntu Updater. When the process finished, Unity desktop freezed, although the mouse pointer was still responsive. I did a system reboot, but once when my session was open:

1. Unity launcher was freezed, with no icons (white squares were placed instead of them).
2. Global menu was freezed.
3. No icons in the right-upper corner of the screen (wifi indicator, keyboard language button, bluetooth icon, etc, wheren't displayed).
4. Mouse pointer was responsive, it didn't freeze.
5. When the icons of the top bar finally appeared, they reacted very slowly to the mouse clicks.

I tried to solve this issue with sudo apt-get install --reinstall ubuntu-desktop, but it didn't work.

Using:

Ubuntu 14.04, 64 bits.
NVIDIA GeForce 6200, with official NVIDIA driver (installed with 'additional drivers' tool).

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: unity 7.2.4+14.04.20150316-0ubuntu1
ProcVersionSignature: Ubuntu 3.13.0-48.80-generic 3.13.11-ckt16
Uname: Linux 3.13.0-48-generic x86_64
NonfreeKernelModules: nvidia
.proc.driver.nvidia.agp.gpu:
 Fast Writes: Supported
 SBA: Supported
 AGP Rates: 8x 4x
 Registers: 0xff000e1b:0x1f000302
.proc.driver.nvidia.agp.host.bridge:
 Host Bridge: PCI device 1106:0204
 Fast Writes: Not Supported
 SBA: Supported
 AGP Rates: 8x 4x
 Registers: 0x1f000a0b:0x00000b02
.proc.driver.nvidia.agp.status:
 Status: Enabled
 Driver: AGPGART
 AGP Rate: 8x
 Fast Writes: Disabled
 SBA: Enabled
.proc.driver.nvidia.gpus.0: Error: [Errno 21] Is a directory: '/proc/driver/nvidia/gpus/0'
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 304.125 Mon Dec 1 19:58:28 PST 2014
 GCC version: gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)
ApportVersion: 2.14.1-0ubuntu3.10
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
Date: Thu Apr 23 17:38:24 2015
DistUpgraded: Fresh install
DistroCodename: trusty
DistroVariant: ubuntu
GraphicsCard:
 NVIDIA Corporation NV44A [GeForce 6200] [10de:0221] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: eVga.com. Corp. Device [3842:a403]
InstallationDate: Installed on 2014-11-22 (152 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-48-generic root=UUID=0bbaee34-88b2-46e9-9fd2-9d7efa698bdc ro quiet splash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/18/2005
dmi.bios.vendor: Phoenix Technologies, LTD
dmi.bios.version: 6.00 PG
dmi.board.name: K8M800-M2
dmi.chassis.type: 3
dmi.modalias: dmi:bvnPhoenixTechnologies,LTD:bvr6.00PG:bd09/18/2005:svn:pn:pvr:rvn:rnK8M800-M2:rvr:cvn:ct3:cvr:
version.compiz: compiz 1:0.9.11.3+14.04.20150313-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.56-1~ubuntu2
version.libgl1-mesa-dri: libgl1-mesa-dri 10.1.3-0ubuntu0.4
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.1.3-0ubuntu0.4
version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.15.1-0ubuntu2.7
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.8.2-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.3.0-1ubuntu3.1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.910-0ubuntu1.4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.10-1ubuntu2
xserver.bootTime: Thu Apr 23 17:37:57 2015
xserver.configfile: default
xserver.devices:
 input Power Button KEYBOARD, id 6
 input Power Button KEYBOARD, id 7
 input HID 04f3:0103 KEYBOARD, id 8
 input HID 04f3:0103 KEYBOARD, id 9
 input USB Optical Mouse MOUSE, id 10
xserver.errors: open /dev/fb0: No such file or directory
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:

xserver.version: 2:1.15.1-0ubuntu2.7

[Roberto González Correa (rob-e-gonzlez)]

It seems to be related to proprietary Nvidia drivers: I 'solved' the issue by removing Nvidia 304, and going back to the default nouveau driver.