I had the same issue as Colin had. After a number of frankly useless calls to Elonex, Waterstones and Adobe, I eventually sorted it myself. Apparently after you install the update, you also slightly change the id of the device so even though Adobe Digital editions still see's it, it's not allowed to add bought EPUB files to it. To fix this, you need to go to page 4 off the settings menu, and deactivate the DRM setting. Once you've done this then when you reconnect to your PC and start Adobe DE, it will ask you to re-authorise your new reader. Once done, your bought books (which might need to be reloaded onto the reader, not sure on this bit as I had deleted all mine of the reader first) should work fine. Hope this helps.