I have lost almost half a day trying to connect my Sony Reader to my MacBook Air after upgrading to OS 10.11. I finally called the Sony Help Line where I was told that Sony does not support Mac OS higher than 10.8.. Great way how to treat your customer I thought as this news does not appear on any Sony document. The Help Line guy was, however, very helpful and told me I should feed my Reader through the Adope Digital Edition Program which I did and it works. It is, however, important that you eliminate the Reader Program from you Program Folder before downloading books into Digital Edition.The download to the Reader is not automatic but you can copy the .epub file of the book from the Adobe Digital Edition. You will find the .epub file in Documents/Digital Editions on your Mac. Link the Reader to the Mac, say yes, open the Reader Icon that will appear (forget the Setup Icon), go to the Folder Reader, then to Folder Sony Reader then move the .epub file into the Folder Books. That's it ! By the way, I have blacklisted Sony.... but their helpline was great. Before I forget, if you want your library that sits on the Reader on the Mac you can copy all the .epub files from the "Books" Folder on the Reader to the Documents/Digital Edition Folder. Hope this works for you - it did for me.