> + PVE::QemuServer::add_unused_volume($conf, > $old_volid); > + PVE::QemuServer::update_config_nolock($vmid, $conf, > 1); I am not sure that above code is correct. The volume is "used" inside a snapshot, so why do you add it to add_unused_volume()? (it is 'used' - not 'unused')