Mon Jun 12, 2017 10:00 pm
Hello,
Please try this (as an admin)
Close Blender
Move the yafaray_v3 folder from the AddOns folder in the user roaming, etc, to C:\Program files\Blender, etc\addons
I'm starting to suspect two possible causes here:
A) the tilde in your user last name
B) or perhaps you have other YafaRay versions or The Boumty in the progeam files\blender, etc\addons foldrt
I hope this helps, going to bed now, very tired...