I have the same problem using two different external Portable drives (Seagate Free Agent & Seagate Expansion). Initially these drives were recognised and I was able to view (Video) and listen (Music) to content recorded on them. However, after disconnecting to add content and reconnecting I was encountered with the No Storage problem reported by others.
I add to their postings simply to reinforce that this does not seem to be a unique problem affecting one or two individuals and calls for some attention.