Error starting Domain: 'utf-8' codec can't decode byte 0x97 in position 153: invalid start byte

I never manually modified xml. I only use the virt-manager ui.

Fehler beim Starten der Domain: 'utf-8' codec can't decode byte 0x97 in position 153: invalid start byte

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/asyncjob.py", line 111, in tmpcb
    callback(*args, **kwargs)
  File "/usr/share/virt-manager/virtManager/object/libvirtobject.py", line 66, in newfn
    ret = fn(self, *args, **kwargs)
  File "/usr/share/virt-manager/virtManager/object/domain.py", line 1279, in startup
    self._backend.create()
  File "/usr/lib/python3/dist-packages/libvirt.py", line 1234, in create
    if ret == -1: raise libvirtError ('virDomainCreate() failed', dom=self)
  File "/usr/lib/python3/dist-packages/libvirt.py", line 37, in __init__
    err = libvirtmod.virGetLastError()
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x97 in position 153: invalid start byte