As an aside, a shader like HSS is not a plugin so it won't appear in the About Installed Plugins list.

*Thank you for clearing that up. I was only trying to cover all bases. The reason I suggested not reinstalling DS4 is because when I tried it, (my version was giving me the same problem), it did not fix it. Also, I did not reinstall the content library, since it was not the content that was causing the problem. I went through two weeks of frustration trying to fix the problem. I searched the internet every day, and finally I found the cause on my own. The specular and ambient settings were wrong. Reflection settings compounded the problem. So I backed off on the sliders for each, doing a test render each time. and began seeing improvements. It can be a problem when the workspace won't show the effects of what you do with those settings and with shadowing until it is rendered in 3Delight.

Anyway, if it will fix the problem, go ahead and reinstall. I hope it works for you.