Comment 18 for bug 350776

I encountered the same problem in 9.04 after trying to change Appearance settings. Hardware is nVidia 160m in Dell E6500. I've always hated nVidia's stance on open source; this just brings back bad memories.

I noticed this in my pstree:

     ├─jockey-backend─┬─cdrom───mount
     │ └─{jockey-backend}

and top showed:

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
 3885 root 20 0 16664 1740 1452 R 24 0.0 8:55.71 cdrom
 3790 root 20 0 180m 70m 16m S 14 0.9 4:43.00 jockey-backend
 2529 messageb 20 0 22064 1792 808 S 6 0.0 2:42.00 dbus-daemon

So I disabled 'local cdrom' in my Synaptic settings and retried. At first it didn't work, but then I realized the above 'cdrom' process was still running. So I killed it, and this time it seems to work (at least it downloads and installed). I'm about to reboot and confirm.