This is the exact same problem I am having. Extremely frustrating! The problem is recent. Previously I never had any difficulties transferring books from my desktop ADE to my Kobo and reading them on my Kobo. I am adding my comments here in the hope that someone will see our plea for help and resolve our difficutlies. Now, I am able to read library books in ADE 4.5.1.133054 on my Macbook running OSX 10.11.2, and I have no problem transferring files to my Kobo. But when I try to open them on my Kobo, I get the same message: "Oops! This document couldn't be opened" due to DRM issues. My Macbook and Kobo both have the same valid adobe ID authorization. I can also download and open Toronto library books onto my iPad and read them in the Overdrive app. I have done a factory reset on my Kobo, ensured that the Kobo is running the latest version, uninstalled and re-installed ADE on my Macbook, deauthorized and reauthorized both my Macbook and Kobo. Nothing has worked.I am stuck! Do any other readers out there have any suggestions? Thanks
... View more