Uninstalling VMware Tools and reinstalling it fixes the problem with unity on the Windows 8.1 guest but not Windows 10.
From mbaran's post it looks like unity is not supported with Windows 10 because of some fundamental changes that Microsoft has made with desktop rendering.
I have attached my logs just in case you need it and it helps.
I guess that I will continue to use the 8.1 guest until the issues with 10 are resolved.
Thanks,
Harish