overlayfs: missing 'workdir' on CloneZilla start

This probably has to do with the fact that for a ready only mount (which is probably the case for a clonezilla usb key) a workdir is not needed and is left blank in the OverlayFS mount config. Thus the notice is saying that it is missing, but in this case that is nothing to worry about.

You can just go ahead and clone your partition!

I just downloaded the stable version and had the same error as you. I tried to used a previous version, it displayed the message but immediately continued. I suspect we have some incompatibility with the latest version.