Not able to open library books on my Kobo Glo: "Oops! This document couldn't be opened"

This issue has never been fixed. I've tried every workaround/fix out there and sometimes the problem is temporarily resolved but it reverts. From what I read from those seeking support, Adobe blames Kobo OS and Kobo blames the ADE application. Going back to ADE 3.0 might work but it is not compatible with the current M1 Macs so attempting to install it only causes a resinstall of 4.5. ADE is probably the worst Adobe product ever made, and the least supported. (The iOS version is shockingly bad as well.) My only options are to stop borrowing ebooks from my library or buy a new Kobo that has the Overdrive app installed for direct downloads of borrowed books. I resent having to replace a perfectly good device just because ADE doesn't work as it should.

I am incurring the same issue now with my Kobo Glo HD. I originally downloaded ADE 4.5, authorised the computer, authorised the device, and transferred the books from my library to Kobo Glo HD, but afterwards, I got a message on my Kobo saying "Your eReader has been deauthorised. You will no longer be able to read any books protected by Adobe Digital Rights Management (DRM) that you imported using Adobe Digital Editions (ADE)."

I've deauthorised my device and reauthorised it. I've tried deauthorising my computer and reauthorising too, but all attempts failed. 

I uninstalled ADE 4.5, deleted all books and files on my Mac, and installed the ADE 3.0 version, but unfortunately got the message: 

“Adobe Digital Editions 3.0.app” needs to be updated."

I can read borrowed EPUB books from the Toronto Public Library (Canada) and the Waimakariri Library (New Zealand) on ADE, but it seems as though there's an issue transferring the files over to my Kobo. 

Can't believe this issue has been going on for so many years... someone please help! 

Do people who have Kobo Clara have this issue too? 

It's frustrating to see that this question was asked 2.5 years ago and the problem still occurs for some people. I got my Kobo for Christmas last year, so it's not even been a year. This isn't the first time I'm having problems, but it's the first time I just cannot fix it. I have tried everything suggested in this thread, and every other suggestion I came across when I googled the issue. Nothing works. I have spent probably about ten hours in the past week trying to read books I both bought and borrowed. I can't. Many times when I want to tackle the problem again, I can't even get my Kobo to show up on my laptop/in ADE. This is entirely ridiculous. I simply do not understand how Kobo and Adobe can continue to blame the other company and not fix the issue. The idiots are your customers who have to spend hours trying to fix something they didn't break, with no guarantee that it'll work. If this was a recent issue with hope remaining that it'll be fixed, ok. But a Google search shows me threads that date back 5 or more years, and there is still no solution that fixes it for everyone. Or even better yet, a fix so that this issue doesn't even occur anymore.

Now I'm left with an ereader that has no books. If I can make it work again, I will have to download all of the books again and transfer them again. I pretty much have an ereader I cannot use. I have wasted countless hours fixing issues since I got this ereader, with more or less success. This is entirely ridiculous.

Well that's super frustrating.  I never used to have trouble downloading library books to my Kobo and now I can't.   I don't ever actually buy books and went with a Kobo specifically because I could download the ePUB format.  Ugh.   What a pain in the rear.   I guess I'll have to rely on audiobooks and Overdrive on another device.   Kobo rendered useless.

I do not think it's  problem we have with ADE, but with KOBO.  The library books are downloaded on the computer, but KOBO blocks the download to the e-reader, because they are in the business of selling their books. Sometimes after I bought books 3/4 times I can download the library books for a while. As if the "portal" would be left open.

I had all the same issues described in this blog, and I spent 2 days of agony to get my new Kobo Aura One e-reader to accept public library books.

Adobe Digital Editions required to download public library books and then transfer them to my Kobo. Couldn't get the Adobe account authorization to stick on the Kobo. Books downloaded appropriately to my computer and were visible in ADE. Computer was properly authorized, and I could read the books on my computer. Books appeared to transfer to the Kobe, but when disconnected from computer, the books were grayed out on the Kobe and wouldn't open with an error message saying the Kobe was not authorized to read said public library books.

I tried all the tricks suggested in this blog... reauthorizing both the computer and e-reader.... many times. Reset the Kobe to factory settings... many times. Returned books to library and downloaded again and again. Tried new books from library. Reloaded Adobe Digital Editions... version 4.5.7. Once I was able to get a single book onto the Kobe and able to read it.... not sure exactly what sequence of actions enabled it. But when I added another book... everything went blank again and the Kobe kept insisting that it was not authorized (even though on my computer, the ADE said that my Kobe WAS authorized.)

Eventually I got a new error message on the Kobe saying that it was not authorized because I had too many “devices” previously authorized. (I'm thinking that maybe every time I reset the Kobe to factory setting that the Adobe Digital Editions (ADE) was incrementing and the Adobe system assumed I had multiple devices.) An Adobe blog for this problem said I needed to contact Adobe for them to reset my account. Well, that was a nightmare in itself... almost 2 hours of “chatting” with 2 different individuals who must have failed 5^th grade spelling and grammar. They insisted that for proper authorization I should read Adobe on-line blogs. I insisted that I had spent hours doing just that and that the blogs told me to contact Adobe Customer Service to reset my account. Finally they did it... and I was able to authorize my Kobe.

But... there was still another problem lingering that I didn't mention previously... Remnants of previous books remained and showed up on ADE... by this time I had 12 books showing... all grayed out. (These are books that I had “returned” to my public library.) I had read another blogger who indicated that these remnants had a time stamp and that they would go away after a day or two... Yes, I agreed with that... otherwise I would have have maybe 20 “books” in the system. I finally figured out that these “remnants” were being re-entered from the Adobe “cloud-sync”. I knew this because I deleted all book remnants from “My Digital Editions” folder in my computer “Documents”. When I closed and then reopened ADE... they all came back. Deleted them once again and turned off my wi-fy. They didn't come back. I concluded I did not need Adobe's “Cloud-sync”..... Solution: ADE version 3.

Conclusion: Reset ADE account, delete all previous book references, delete all “Cloud-sync” folders, and install ADE 3.0.  

This is all relating to Kobo e-readers, but what about the unlucky ones (me...) who are still using Sony PRS-T1 e-reader? Is the only solution to buy a new e-reader and pray that it will work then???

After buying a few ebooks recently, I converted them into epub files in ADE and copied them into Sony PRS-T1. SImilar to you all, I get the error: "secured by digital rights management". I tried updating the e-reader, converting the authorisation of my PC to my old Adobe account to see if my e-reader had maybe been connected to that account, but still no luck.

I have contacted our friends at Adobe support a few times, but they keep referring me back to these forums and quickly close the chat before I can answer.

Anyone else who can help me out?

The newest Kobo update fixed the problem.

I too have tried everything on this thread multiple times without success ... hours of effort wasted!  The curious thing for me other than the fact this has been going on for years now without a fix is that my wife and I have KOBO's of the same vintage.  Her's got the disease about 6 months ago and mine didn't.  We are running the same software versions on our KOBO's.  We use the same Adobe ID on ADE for library downloads of EPUB's.  Her KOBO is authorised on her account only with the same ID as her authorised computer.  Mine is authorised on her account (as well as another account with a different Adobe ID) and we use the same computer authorized on her Adobe ID for downloads.  Mine works on both ADE version 3 and 4.5.4 her's doesn't work on either  ... we just keep getting the infamous "oops" message.  Her KOBO works fine for other books purchased from KOBO so it seems that the ADOBE/Overdrive/KOBO engineers need to get their heads together to determine who owns this issue!!

I am having the same problem, and like many others have tried everything suggested with no success. Is there a solution to this?