This morning's update broke my CentOS VB VM

[compdoc]

> pdmblkcache#0: The VM is missing a block device. Please make sure


I use qemu-kvm and got similar errors after upgrading. Since you use VB this
may not be the same problem, but I had to edit the .xml file that defines
the VM and replace the word 'raw' with 'qcow2' for any VM using the qcow2
format. The newer version of qemu-kvm was upset if you had it wrong.

I also had to change the 'machine' type for a couple of VMs from 'rhel5.4.0'
to 'pc', but that's a separate error...