Comment 14 for bug 1264465

No luck, same problem with the VM powered on.

Path '/dev/bus/usb/000/000' is not accessible: No such file or directory

Traceback (most recent call last):
  File "/usr/share/virt-manager/virtManager/addhardware.py", line 1168, in add_device
    self.vm.attach_device(self._dev)
  File "/usr/share/virt-manager/virtManager/domain.py", line 841, in attach_device
    self._backend.attachDevice(devxml)
  File "/usr/lib/python2.7/dist-packages/libvirt.py", line 419, in attachDevice
    if ret == -1: raise libvirtError ('virDomainAttachDevice() failed', dom=self)
libvirtError: Path '/dev/bus/usb/000/000' is not accessible: No such file or directory