Cloning error : Error executing wimcapture

Version: Winclone 6
Hardware: Mac Pro 2009
OS: 10.13.6
Bootcamp
Windows10 on a separate SSD

When I run the Winclone, get the error and bootcamp disconnects.

I suspect that the Mac Pro uses legacy booting so external booting is probably not possible (or more difficult than I can figure out!).

tim