Comment 3 for bug 330824

I had experienced the same, and reported it at https://bugs.launchpad.net/ubuntu/+bug/334581. I have had to hard reset my computer four times today.

The circumstances were the same all 4 times: I was copying large directories between different ext4 partitions (using nautilus) when the system locked up. The directories in question have tens of thousands of small sized files. I am going to mark bug 334581 as a duplicate of this one so that we can focus our discussion and testing on one bug report.