[ovirt-users] Error setting cluster level to 4.2

Hello, after upgrading engine (external) and the 3 hosts composing the cluster, I try to set its level to 4.2 but I receive this kind of message " Error while executing action: Update of cluster compatibility version failed because there are VMs/Templates [ov42, ovlive3, ovlive4, ovlive1, ovlive2] with incorrect configuration. To fix the issue, please go to each of them, edit, change the Custom Compatibility Version of the VM/Template to the cluster level you want to update the cluster to and press OK. If the save does not pass, fix the dialog validation. After successful cluster update, you can revert your Custom Compatibility Version change. " The ovliveN VMs are diskless where I boto from the oVirt live iso for testing and ov42 a nested single VM where I tested the oVirt 4.2 environment before upgrade of the real cluster. I suspect that the problem could be related with macspoof custom property set to true. Is this? In case how can I manage this sort of problem? Can't I have macspoof in 4.2? Thanks, Gianluca