Comment 2 for bug 696318

Thank you for taking the time to file this report and helping to make Ubuntu better.

The information in the description shows that level3.img is owned by root:root, and that the reason for not being able to use level3.img was due to permission being denied. Could you chown libvirt-qemu:kvm /tmp/level*.img, and try again?

Note: since libvirt chowns the files before using them, it actually seems more likely that level2.img or level1.img would be the problem. I can devise one or two sequence of events and experiments which would cause one of the base image files to be inaccessible to libvirt. That might be a real bug worth bringing up upstream.