cgroup backend for pathOfController error

After installing Whonix-XFCE- the gateway starts as expected and runs flawlessly. Nevertheless, the Workstantion will not start with the following message:

Error starting domain: internal error: failed to get cgroup backend for 'pathOfController' (Full traceback bellow).
In the environment I have also installed Tails and Debian 11. They all work fine, so I guess this is an issue that has to do with Whonix Workstation only.

I have a vague idea about what cgroup is, but do not have any ideas on how to do anything about it.

Any hints will be much appreciated.


  File "/usr/share/virt-manager/virtManager/", line 65, in cb_wrapper
    callback(asyncjob, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/", line 101, in tmpcb
    callback(*args, **kwargs)
  File "/usr/share/virt-manager/virtManager/object/", line 57, in newfn
    ret = fn(self, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/object/", line 1329, in startup
  File "/usr/lib/python3/dist-packages/", line 1353, in create
    raise libvirtError('virDomainCreate() failed')
libvirt.libvirtError: internal error: failed to get cgroup backend for 'pathOfController'```

Late, but try this and see if the problem goes away:

the control group (cgroup) reference the integration of the KVM virtualization with physical resources. In this case the possible pathOfController could be the connection between KVM and the CPU. If your CPU has for example only 1 physical processor with some virtual cores, the parameter cpuset should be “0” in the vcpu tag: “<vcpu placement=“static” cpuset=“0” …” inside the XML config file of the VM whonix workstation in KVM, referencing the first and only physical cpu.

@HulaHoop the suggestion that you share, only works for Arch linux and Ubuntu, is that correct?

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I don’t know since I only work with Debian.

I had the same problem from this thread and changing this field worked for me. Thanks!

An additional step to take (for anyone else having the same issue) is that the Workstation has to be reloaded:

$ sudo virsh -c qemu:///system undefine Whonix-Workstation
$ sudo virsh -c qemu:///system define Whonix-Workstation*.xml

I’ve always used VirtualBox where you can change settings on the UI, but it seems on KVM you must reload the whole settings from the XML file.

You need to restart the VM for changes to take effect not reimport the whole settings file.