Try and open a VM:
Could not open /dev/vmmon: No such file or directory.
Click Ok
Please make sure that the kernel module `vmmon' is loaded.
Click Ok
This just started happening when I try and open a VM from Fusion 8.5.10. Uninstalling and Re-installing VM Fusion doesn't help. This is on a Mac (Mojave OS). Also don't get anything in Security and Privacy in Mac like I have seen on other posts.