I have moved Poser 8 out of the Program Files folder.  I felt I had nothing to lose and a lot to gain if it worked. I left the Poser Content where it was.

Poser 8 seems to run a lot faster and so far (touch wood) it has not choked on the libraries. There isn't even a pause when it loads up on startup.  I was able to access the Props category in the new Poser 8 content, and I had not been able to do that before. This is very exciting. I'll play around some more and see if this is a lasting solution. It certainly looks promising.

Mariner, I thank you for the sage advice.

Poser 11 Pro, Windows 10

Auxiliary Apps: Blender 2.79, Vue Complete 2016, Genetica 4 Pro, Gliftex 11 Pro, CorelDraw Suite X6, Comic Life 2, Project Dogwaffle Howler 8, Stitch Witch