Close all applications.
Press WINDOWS + R.
In the Open text box, type regedit and then press Enter. The Registry Editor opens.
In the left pane of the Registry Editor, locate the following registry key: HKEY_CURRENT_USER\Software\Adobe\Adept
Remove the Adept Folder.
In the Confirm Key Delete dialog, click OK.
Close the Registry Editor.
Open Adobe Digital Editions and reauthorize..
quit Adobe Digital Editions.
Navigate to /Users//Library/Application Support/Adobe/Digital Editions and drag the activation.dat file to the trash.
If you are using 10.7, see https://helpx.adobe.com/x-productkb/global/access-hidden-user-library-files.html
Open Adobe Digital Editions and reauthorize.
"Navigate to /Users//Library/Application Support/Adobe/Digital Editions and drag the activation.dat file to the trash."
I have tried this, but both the digital editions map and the file activation.dat do not exist in the Application Support/Adobe directory.
Any other suggestions? I think I have tried now every option suggested in the community (de-authorising ADE, deleting ADE and reinstall it, updating it (it is up to date), deleting the (non-existent) activation.dat file).
You in the right library folder? Have you used the steps under the link?
There is no such file on my computer, at least, I cannot find it with the Finder. I have used the steps under the link. The ~Library folder is not hidden. Any other suggestions?
The search the file not found.
You has two Librarys under your System.
You are used which os?
I use high sierra
We are all having the same problems putting ebooks on e-readers.
When you just like to read ebooks and you are not interested in playing with computers Adobe Digital Editions really is horrible.
I do not understand why Adobe is thinking that problems can be solved by the way they support (with registerchanges, etc.) people who just want to read. Incredible.
I too have tried all of the suggestions and failed, mine is on a PC. The only idea I have left is that DE works fine on another PC with a different identity. I am beginning to think that because I use an Adobe ID with Creative Cloud that there may be some kind of conflict on my PC. Every time I remove the Key file from the registry the PC just puts it back again. Of course, I get no response from Adobe. I just wish there was an alternative software that I can pay for and get proper support!