I think I solved this in Fusion 10 on MacOS High Sierra won't run any VM post #22.
Shut Fusion down and use Finder (not any other file manager) to move the VM Ware Fusion.app to another folder and then back into the /applications folder (you need admin rights). Then start Fusion again and it should mention a security problem with the kernel extensions that you need to allow in the security settings of OS X.