Parallels Desktop user interface crashes when Mac has Italian language set in System Preferences during an attempt to access the Devices menu.
Refrain from using the Devices/Dispositivi menu until the fix is released. Subscribe to this article to get an update about the fix.
As a workaround, use the virtual machine configuration to change devices settings, e.g. networking.
For external/USB devices use the USB Controller icon on virtual machine window header:
This menu is available only in Window mode or in Full Screen (move your mouse to the top of your screen in Full Screen mode to see it).
If you run Windows in Coherence mode, exit it first.