I am running vmware workstation 11 on windows 10, and it seems Unity mode doesn't work.
I've tried both Debian (jessie and stretch) with gnome-fallback (metacity), kde, and xfce as well as Ubuntu 15.04 with xfce & gnome-fallback (metacity) as guests. Every time I tried to enter Unity i get the message
The virtual machine cannot enter Unity mode. Check that Unity is supported for this guest operating system and that the latest version of VMware Tools is installed.
open-vm-tools-desktop installed on all of them. I also ran the vmware-tools installer after to install all it's kernel modules and whatever else it does.