I found an answer at the following blog:
Dixin's Blog - Run Hyper-V and VMware virtual machines on Windows 10
Thanks Dixin!
Finally, after pulling my hair out, what is left of it, I found a work-around. When you reboot, it will ask you two security questions, you must respond with F3 for both. After rebooting Workstations works.. (For some reason, I had to take ownership on one of my VM's, because I couldn't get in to it.
TasP