Opensim Library shows "Loading..." for top level folder and all sub folders. This never resolves. As a result, any avatar relying on one or more of the mandatory Body Parts from this folder tree to make their avatar show in their viewer will see a perpetual cloud.
The work around is to turn off "http inventory fetches" usually under the Advanced / Network sub menu of a viewer, but this may be viewer dependent. This allows the Opensim Library folders to populate and the avatar will then appear in their viewer.