Unity wont start at boot

What GPU do you use?
Which release did you upgrade from?

Some hardware isn't capable of initialising Unity
Or it could be that you have selected "Classic Ubuntu" on the login manager (which will load gnome)

I have an nvidia GPU.
lspci reports:
VGA compatible controller: nVidia Corporation G96 [GeForce 9500 GT] (rev a1)
I upgraded from 11.04 to 11.10
During the upgrade, when prompted to choose gdm or lightdm, I chose gdm, which did not work.
I purged it, installed lightdm, and installed Unity.
I guess i was hoping that those two packages would "get the configuration right" and things would be OK.

I will post Xorg log if that will help.
Thanks.

Can you give the output of:

sudo lshw -C display; lsb_release -a; uname -a

Thanks

  *-display
       description: VGA compatible controller
       product: G96 [GeForce 9500 GT]
       vendor: nVidia Corporation
       physical id: 0
       bus info: pci@0000:04:00.0
       version: a1
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress vga_controller bus_master cap_list rom
       configuration: driver=nvidia latency=0
       resources: irq:16 memory:bf000000-bfffffff memory:c0000000-dfffffff memory:bc000000-bdffffff ioport:e800(size=128) memory:bef80000-beffffff
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 11.10
Release: 11.10
Codename: oneiric
Linux media 3.0.0-16-generic-pae #29-Ubuntu SMP Tue Feb 14 13:56:31 UTC 2012 i686 i686 i386 GNU/Linux

Ok and the output of:

dpkg -l | grep nvidia

Did you upgrade your OS to get Oneiric or is it a clean install? If you did, which release did you upgrade from?

I upgraded the system from 11.04 to 11.10.

dbuttric@media:~$ dpkg -l | grep nvidia
rc nvidia-173 173.14.30-0ubuntu1 NVIDIA binary Xorg driver, kernel module and VDPAU library
rc nvidia-common 0.2.23 Find obsolete NVIDIA drivers
ii nvidia-current 280.13-0ubuntu6 NVIDIA binary Xorg driver, kernel module and VDPAU library
rc nvidia-kernel-common 20080825+1ubuntu2 NVIDIA binary kernel module common files
ii nvidia-settings 280.13-0ubuntu2 Tool of configuring the NVIDIA graphics driver

sudo dpkg -P remove nvidia-173 nvidia-common nvidia-kernel-common; sudo apt-get --purge remove nvidia-current nvidia-settings

Then reboot and run:

sudo apt-get install nvidia-curret nvidia-common

Should be ok

That did not help the situation...

Is it possible that apparmor is getting in the way here?
I see this in my syslogs:
syslog:Mar 11 12:32:54 media kernel: [ 50.917413] type=1400 audit(1331487174.501:16): apparmor="STATUS" operation="profile_load" name="/usr/lib/lightdm/lightdm-guest-session-wrapper" pid=1043 comm="apparmor_parser"
syslog:Mar 11 12:32:56 media kernel: [ 52.737836] init: lightdm main process (1159) terminated with status 1
syslog:Mar 11 12:38:18 media kernel: [ 34.525211] type=1400 audit(1331487498.000:7): apparmor="STATUS" operation="profile_load" name="/usr/lib/lightdm/lightdm-guest-session-wrapper" pid=1048 comm="apparmor_parser"

How does one go about reconfiguring apparmor?

Thanks for your help.

sudo dpkg-reconfigure apparmor
Did not help the situation.

I'm not conversant with apparmor. When do you get those messages?

My problem is that its been so many years since I had to troubleshoot any of this, that I cant remember any of it any more.

I'm tired of trying to solve this.
I installed gdm again, and that is working for me.

When I have time to rebuild this machine, I will install Unity, and use lightdm. I'm sure that there is a broken config somewhere that was still looking for gdm somehow, and that is why lightdm was not starting...

Thanks alot for all your help.

Have a great sunday.