While creating first virtual machine in KVM on Ubuntu 14.04 got Error : Unable to complete install:’unsupported configuration hda-duplex not supported in this Qemu binary’.
Note: It was my fresh installation of KVM on Ubuntu 14.04 LTS.
Solution : Restart libvirt-bin.
sudo stop libvirt-bin sudo start libvirt-bin
Reopen the virt-manager. I hope the problem is solved.
Run the below given command in terminal for opening virt-manager.