Did you go to the site and download the new client:
You’ll have to Log In once you start the client! :-)
The deal is, of course, that someone has to invite you to share such-and-so folder. Fine. My correspondent in Australia has done so, BUT...the invitation -- by the time it got to me -- had been somehow aliased: instead of receiving an invitation to share from Bill Gibbs, I received one from Mark Jones.
As you probably suspect, I spoke to Bill about it, and he DID send an invitation, but is as puzzled as I about the weird name. We both think that I'm sharing (something) with Jones, but who cares, right?
This is wild. Also incompetent, but, what the hell, it's MS, true?