I'm trying to create a CentOS virtual machine in Debian Buster using virt-manager with QEMU/KVM. I had installed it with:

$ grep -o 'vmx\|svm' /proc/cpuinfo 
$ sudo apt install qemu-kvm libvirt-clients libvirt-daemon-system bridge-utils libguestfs-tools genisoimage virtinst libosinfo-bin virt-manager
$ sudo adduser $USER kvm
$ sudo adduser $USER libvirt
$ sudo adduser $USER libvirt-qemu

Every time I attempt to install the virtual machine using the iso, however, I always get the following error:

   Unable to complete install: 'unsupported configuration: unknown protocol type 'file''

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 75, in cb_wrapper
    callback(asyncjob, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/create.py", line 2119, in _do_async_install
    guest.installer_instance.start_install(guest, meter=meter)
  File "/usr/share/virt-manager/virtinst/installer.py", line 419, in start_install
    doboot, transient)
  File "/usr/share/virt-manager/virtinst/installer.py", line 362, in _create_guest
    domain = self.conn.createXML(install_xml or final_xml, 0)
  File "/usr/lib/python3/dist-packages/libvirt.py", line 3732, in createXML
    if ret is None:raise libvirtError('virDomainCreateXML() failed', conn=self)
libvirt.libvirtError: unsupported configuration: unknown protocol type 'file'

Both the minimalist and the DVD iso files from the CentOS website and even the Debian Stretch iso bring up the same error.

1 Answer 1


What helped me to solve this issue was to create a new pool in the "Choose Storage Volume" window including the ISO image of the OS I wanted to install. Next, I selected the ISO image from this pool when selecting an ISO image in step 2 of 5 of the "Create a new virtual machine"-guide of the virtual machine manager.

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