Ciao !
Ho lanciato virt-manager ma quando ho cercato di creare la nuova macchina virtuale ho ricevuto questo messaggio :

" During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/share/virt-manager/virtManager/manager.py", line 451, in new_vm
from .createvm import vmmCreateVM
File "/usr/share/virt-manager/virtManager/createvm.py", line 30, in <module>
from .storagebrowse import vmmStorageBrowser
File "/usr/share/virt-manager/virtManager/storagebrowse.py", line 11, in <module>
from .hoststorage import vmmHostStorage
File "/usr/share/virt-manager/virtManager/hoststorage.py", line 16, in <module>
from .createpool import vmmCreatePool
File "/usr/share/virt-manager/virtManager/createpool.py", line 18, in <module>
from .xmleditor import vmmXMLEditor
File "/usr/share/virt-manager/virtManager/xmleditor.py", line 14, in <module>
gi.require_version("GtkSource", "3.0")
File "/usr/lib64/python3.7/site-packages/gi/__init__.py", line 130, in require_version
(namespace, version))
ValueError: Namespace GtkSource not available for version 3.0 "

Grazie.