I just got my 505 recognised by my Mac and the same with my wife's book on her Macbook.
Having wasted ages with Waterstones I was put onto Sony support and advised to remove Adobe Digital Editions. (Finder > Applications >Drag and drop ADE into the Trash) Remove Ebook Library in the same way. Go to Sony UK support and download a new version of the library, again. Restart. Connect the eReader and open the library. Voila, as they say in Guatemala, it works. I can now buy, download and transfer books. Thank you Sony support for your patience while it all happened.
Now all I need is for some charitable soul to inform me (via PM) how torrents work and DRM removal, because I am fed up being ripped off buying ebooks at a higher or equivalent price as a hardback, while being limited to a single download. I cannot even let my wife read books I have bought by transferring them to her SD card.
Yup, I'm half happy and half grumpy.
