I can't reproduce it either. Can you run tail -f -n 0 ~/.xsession-errors in a terminal, then try to make it break and copy the output here afterwards?
** Changed in: control-center (Ubuntu) Status: Unconfirmed => Needs Info -- When modifying the volume with the keyboard, Ubuntu sometimes freezes https://launchpad.net/bugs/85875 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs