Screensaver source says Loading... for ever
Photo screen saver hasn't worked properly since the previous upgrade of Aperture to combine libraries with iPhoto.
Post the Mountain Lion upgrade, I can't even configure the screensaver. I call up the panel and I can choose the slideshow type (different arrangement of photo shapes on the sceen), but the source drop down offers only a single option "Loading..." even if I leave it for some time - so I can no longer even choose a folder (rather than part of my Aperture library given that there is a running issue with photos from Aperture in the screen saver).
(I've tried choosing one of the non-photo screensavers and then coming back to a photo one, but it's the same, always Loading... in the drop down and Loading Photos... in the preview panel - but never anything else.
Has anyone else seen this? (who has Aperture - as I guess this is still linked to the problem introduced by the pre-Mountain Lion Aperture update - I've taken the Aperture upgrade that is available immediately after upgrading to Mountain Lion).
iMac, OS X Mountain Lion, Aperture 3.3.2