I have been using Ubuntu 11.10 + Gnome Shell with a Nvidia card, but now I've moved it to my new PC which has an ATI card, at first it wasn't booting but I installed the driver from amd.com and then it worked. Anyway my problem is that gnome-shell is crashing, mostly when I try to start a VirtualBox machine (it happened in other times but I don't remember what I was doing). Sometimes gnome-shell respawns and it continue working but sometimes it doesn't so I have to restart lightdm and lose all the windows I was using. Here's some of the syslog when the crash occurs: Apr 9 12:20:08 desktop-1 NetworkManager[1032]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/vboxnet0, iface: vboxnet0) Apr 9 12:20:08 desktop-1 NetworkManager[1032]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/vboxnet0, iface: vboxnet0): no ifupdown configuration found. Apr 9 12:20:08 desktop-1 NetworkManager[1032]: <warn> /sys/devices/virtual/net/vboxnet0: couldn't determine device driver; ignoring... Apr 9 12:20:08 desktop-1 kernel: [ 4498.689561] warning: `VirtualBox' uses 32-bit capabilities (legacy support in use) Apr 9 12:24:29 desktop-1 gnome-session[1617]: WARNING: Application 'gnome-shell.desktop' killed by signal Apr 9 12:24:45 desktop-1 gnome-session[1617]: WARNING: App 'gnome-shell.desktop' respawning too quickly Apr 9 12:24:45 desktop-1 gnome-session[1617]: CRITICAL: We failed, but the fail whale is dead. Sorry.... Apr 9 12:25:20 desktop-1 kernel: [ 4810.769775] show_signal_msg: 30 callbacks suppressed |----- > Apr 9 12:25:20 desktop-1 kernel: [ 4810.769785] gnome-shell[3427]: segfault at b0 ip b6bd09cd sp bfc9b650 error 4 in libglib-2.0.so.0.3000.0[b6b71000+f7000]** Apr 9 12:25:20 desktop-1 gnome-session[1617]: WARNING: Application 'gnome-shell.desktop' killed by signal Apr 9 12:25:23 desktop-1 kernel: [ 4814.055705] EXT4-fs (sda1): Unaligned AIO/DIO on inode 133295 by VirtualBox; performance will be poor. Apr 9 12:26:55 desktop-1 gnome-session[1617]: Gdk-WARNING: gnome-session: Fatal IO error 11 (Resource temporarily unavailable) on X server :0.#012 Apr 9 12:26:55 desktop-1 kernel: [ 4905.373256] [fglrx] IRQ 56 Disabled Apr 9 12:26:59 desktop-1 acpid: client 1124[0:0] has disconnected Apr 9 12:26:59 desktop-1 acpid: client connected from 3864[0:0] Apr 9 12:26:59 desktop-1 acpid: 1 client rule loaded Apr 9 12:26:59 desktop-1 kernel: [ 4909.700095] fglrx_pci 0000:02:00.0: irq 56 for MSI/MSI-X Apr 9 12:26:59 desktop-1 kernel: [ 4909.701466] [fglrx] Firegl kernel thread PID: 3867 Apr 9 12:26:59 desktop-1 kernel: [ 4909.701625] [fglrx] Firegl kernel thread PID: 3868 Apr 9 12:26:59 desktop-1 kernel: [ 4909.701852] [fglrx] Firegl kernel thread PID: 3869 Apr 9 12:26:59 desktop-1 kernel: [ 4909.702021] [fglrx] IRQ 56 Enabled Apr 9 12:26:59 desktop-1 kernel: [ 4909.861815] [fglrx] Gart USWC size:1280 M. Apr 9 12:26:59 desktop-1 kernel: [ 4909.861817] [fglrx] Gart cacheable size:508 M. Apr 9 12:26:59 desktop-1 kernel: [ 4909.861820] [fglrx] Reserved FB block: Shared offset:0, size:1000000 Apr 9 12:26:59 desktop-1 kernel: [ 4909.861821] [fglrx] Reserved FB block: Unshared offset:f8fd000, size:403000 Apr 9 12:26:59 desktop-1 kernel: [ 4909.861823] [fglrx] Reserved FB block: Unshared offset:3fff4000, size:c000 Does anyone could guide me on how to fix this? Or the proper place where to ask for help.