After I used BalenaEtcher to create a boot usb, a pop-up window appears saying the USB is unreadable. I realise that makes sense, as the USB now contains a boot image, etc.
HOWEVER, I cannot get that pop-up to respond. I cannot act on any of its buttons, and it persists on the screen until I log out.
Does balenaEtcher cause the pop-up? Is this a glitch?
The pop-up might be from Finder, so I have also asked Apple Support Community if they have any suggestions.
macOS Catalina 10.15.3