Im trying to use virt-manager on FreeBSD 12.1 with Xen 4.12.1. I simple trying tom create a Debian 10 amd64 guest using virt-manager. I get this error when trying to create a guest: Unable to complete install: 'Couldn't create storage volume 'debian10.img': 'cannot fill file '/var/lib/libvirt/images/debian10.img': Invalid argument'' Traceback (most recent call last): File "/usr/local/share/virt-manager/virtinst/storage.py", line 682, in install vol = self.pool.createXML(xml, createflags) File "/usr/local/lib/python3.7/site-packages/libvirt.py", line 3429, in createXML if ret is None:raise libvirtError('virStorageVolCreateXML() failed', pool=self) libvirt.libvirtError: cannot fill file '/var/lib/libvirt/images/debian10.img': Invalid argument During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/usr/local/share/virt-manager/virtManager/asyncjob.py", line 75, in cb_wrapper callback(asyncjob, *args, **kwargs) File "/usr/local/share/virt-manager/virtManager/createvm.py", line 2089, in _do_async_install guest.installer_instance.start_install(guest, meter=meter) File "/usr/local/share/virt-manager/virtinst/install/installer.py", line 536, in start_install dev.build_storage(meter) File "/usr/local/share/virt-manager/virtinst/devices/disk.py", line 769, in build_storage vol_object = self._storage_backend.create(meter) File "/usr/local/share/virt-manager/virtinst/diskbackend.py", line 630, in create return self._vol_install.install(meter=progresscb) File "/usr/local/share/virt-manager/virtinst/storage.py", line 692, in install "'%s': '%s'" % (self.name, str(e))) RuntimeError: Couldn't create storage volume 'debian10.img': 'cannot fill file '/var/lib/libvirt/images/debian10.img': Invalid argument' The user which has started virt-manager has permissions to write udner /var/lib/libvirt/images without any problems. the only workaround is to create a raw image using dd and then use that under virt-manager. But the question is why I cannot create the image using virt-manager ?