Hopefully this saves someone doing a Google search some time. Running something like sudo ubuntu-vm-builder kvm trusty tahir on Ubuntu 14.04 at least seems to sometimes generate the following error (emphasis mine):
Preparing to unpack .../linux-image-virtual_3.13.0.52.59_amd64.deb ... Unpacking linux-image-virtual (3.13.0.52.59) ... , stderr: grep: /proc/cpuinfo: No such file or directory This kernel does not support a non-PAE CPU. dpkg: error processing archive /var/cache/apt/archives/linux-image-3.13.0-52-generic_3.13.0-52.86_amd64.deb (--unpack): subprocess new pre-installation script returned error exit status 1 Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.13.0-52-generic /boot/vmlinuz-3.13.0-52-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.13.0-52-generic /boot/vmlinuz-3.13.0-52-generic Errors were encountered while processing: /var/cache/apt/archives/linux-image-3.13.0-52-generic_3.13.0-52.86_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)
Ends up this is an older known bug. Adding --addpkg linux-image-generic seems to work as recently as Trusty Tahir.