13.6 appears to have broken BootCamp VM definitions - the underlying BootCamp installation can still be booted natively, though, so it hasn't corrupted the Boot Camp installation.
Until VMware fixes this, the workaround that other users have offered is to uninstall Fusion 13.6 and re-install Fusion 13.5.2. You may need to re-configure your BootCamp VM in Fusion.