Hi Christophe, I just found out a small issue in GVirDomainDisk setter functions: they always add a new attribute on each call rather than overriding existing value. For example this Vala code: disk.set_guest_device_type (DomainDiskGuestDeviceType.DISK); disk.set_target_dev ("sdb"); ... disk.set_guest_device_type (DomainDiskGuestDeviceType.FLOPPY); disk.set_target_dev ("fd"); Will generate following XML: <disk type="file" device="disk" device="floppy"> <target dev="sdb" dev="fd"/> ... </disk> -- Regards, Zeeshan Ali (Khattak) FSF member#5124