Unpinned Libraries Returning

That’s a little confusing. Do you mean that, if you delete a library that is pinned, it’s still on the pinned list? Are the contents of the library still there? If not, then you’re probably seeing the same thing I reported here, and all you have to do is unpin the deleted library:

If you’re using Settings Sync, you may need to temporarily disable it, as Otto mentions in that thread.