The subject line asks the question.
I can see my own library open on my desktop machine in Fopnu but I don't know if pointing to Drive D: needs any special attention for setup.  How can I troubleshoot that from the desktop?

you can share your files from any drive your OS gives you access to, multiple drives if you so wish..

if you want to give it a test first; create a folder on drive 'd:', put a few files in it, and try adding it to the library.

Yes, thanks for the reply.  All is well.  I asked another on the system to confirm access after a simple search and that was confirmed.