How to close a frozen pop-up window

I am in the process of shutting down my desktop Mac (running OSCatalina) in order to move it to another room. However, after selecting shut down from the menu, a pop-up message appeared reading "Adobe Creative Cloud is needed to resolve this problem. However, it is missing or damaged" and it gives me the option to select "quit" or "repair." I do not need creative cloud anymore and there is nothing saved within it, so I'd like to select "quit" from the message. However, my computer is now giving the spinning wheel and has been like this for some time. I cannot select any of the options. Is it possible to force-quit a pop-up message? What can I do to shut down my computer?