Just upgraded my laptop and Surface RT to Windows 8.1.  At home I'm still running Windows 7.

On Skydrive I have a large set of photos.  Some are viewable on all 3 machines in the Photos app, but there are a number of folders which show as empty if I try to access them with either the Photos App or the Skydrive App on Windows 8.1 (both machines).  When I access on the web on Windows 7 machine, the folders still have the photos in them.