I am in the same boat with this one - I had a fences 2 installation which was working as intended.
I am running the latest Windows 10 Preview build 14342.
I installed Fences 3, and was not prompted for my product key.
Now after rebooting, my fences are visible, but I cannot open Fences 3, either from the Start menu, or via 'right-click, Configure Fences'.
I then subsequently reinstalled, and then reinstalled again after deleting the Stardock folders in Roaming, local, ProgramData, and the registry - this did not fix the issue.
The problem seems to be with Activation - my fences_debug_info.txt file has several lines which contain "ACTIVATION PROBLEM - unable to read SAS License file"
Finally, I would like to try the 3.01 beta, but as I have not been able to activate my Fences 3 installation, it is not available to me in my downloads section.