I have the same problem. Anyone with the Kobo and many other readers can no longer use their readers because Adobe wrote a lousy program in Digital Editions. It definitely does NOT work with Kobo products. I have read the Adobe support pages, chatted with on website and tried hours of things to try to get it to work. After reading from all the Kobo users on this community forum it is clear that Kobo does not work and never will until Adobe fixes this problem. I also spent hours on the phone with a very knowledgeable library employee with decades of experience who says the same thing. As soon as they updated to 4.0 and beyond, now 4.5, the ereaders are not compatible. Pretty frustrating and no phone support. How can a company like Adobe have such terrible updates AND no way to support customers? I sympathize with you. I loved my reader and it is now useless.