Updating a Fedora 16 guest to a Fedora 17 guest via preupgrade gave me the 'Oh no, something has gone wrong!' screen at the GDM login screen. It's quite frustrating to see that screen because you can't switch to a virtual terminal for troubleshooting, or even reboot or shutdown.
To send the key sequence Ctrl+Alt+F2 to the guest to switch to a virtual terminal, use the qemu monitor by pressing
and use sendkey to send the key sequence:
(qemu) sendkey ctrl-alt-f2
Then go back to the guest window by issuing
After logging in as root, I poked in the gdm log files in /var/log/gdm/ and saw the fprint daemon was causing some errors. Removing the fprintd package fixed this, but this is just a workaround, not a solution:
yum remove fprintd