Cyberduck stopped creating zip-archives, a function I've been using for years and never had any trouble with. I did not change settings nor the host. I'm using a sftp (ssh.strato) connection. The menu is not greyed out. It just does not create zip archives. I have no problems downloading folders or performing any other task.
That's really odd, because there obviously is such a folder. My blog runs on this folder, I can open the folder with Cyberduck, change documents etc. I also downloaded the entire folder with Cyberduck after not being able to create a zip and download the zip.