I observed this bug under the following simple configuration:
0. Clean install of 12.04 LTS, with neither 'download packages' nor 'third party software' checkboxes checked.
1. Log into unity; open a terminal and `sudo apt-get install gnome-session-fallback`
2. Log out of unity and log into gnome classic.
3. Open a terminal. Wait. Observe crash.
I observed this bug under the following simple configuration:
0. Clean install of 12.04 LTS, with neither 'download packages' nor 'third party software' checkboxes checked. fallback`
1. Log into unity; open a terminal and `sudo apt-get install gnome-session-
2. Log out of unity and log into gnome classic.
3. Open a terminal. Wait. Observe crash.
No proprietary drivers are in use on this system.