Do you used Windows or Macintosh?
Macintosh. MacBook Air with OS X Yosemite 10.10.5
- 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 Access hidden library files | Mac OS 10.7 and later.
- Open Adobe Digital Editions and reauthorize.
In Windows 10 the path to the activation.dat key is different: Users\AppData\Roamng\Adobe\Adept
I did delete that key, which unlocked the option to Erase Computer Authorization. I entered my password as requested and got the error message, "Unable to Erase Authorization. Please try after some time."
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..