Virsh connects to lxc and not to qemu

After identical installations of Opennebula (using kvm as hypervisor) on different machines one of installations refuges to work. I stead of using kvm the machine uses lxc instead. Trying to connect with “virsh -c qemu:///system” gives the error “no connection driver available for qemu:///system”.
Comparing the different machines, they all have the same qemu packages installed.

Suggestions are welcome,