I tried everything anyone suggested in many different posts. I could not get it to save to my High Sierra Mac OS via any suggested method.
However, using VMWare Converter 6.4, I was FINALLY able to convert my Win10Pro VM running on Parallels 13 to Fusion 11.x by attaching a large USB drive to a USB 2.0 port (because Parallels and Fusion do not see drives attached via my USB 3.0 card). I uninstalled Parallels Tools from my VM, and installed VMWare Converter 6.4 on the VM. Then I set the destination of the converted VM to the USB drive. Finally it worked. Save yourself a LOT of trouble and just attach a USB drive to the VM...