I downloaded the updated 4.5 ADE, thinking it would allow me to enter a new authorization, but no such luck: the old authorization data is still in place. Since I no longer use the provider/email address I was using when originally 'authorizing' this device (MAC Mini Desktop), nor do I have a record of the password originally used for it, I am stymied. The 'Chat' people referred me to this Forum where they say the "technicians" will tell me how to vacate the old ID & password, so that the new ones can be entered. FYI, I have a new 'Adobe' ID and and new 'Adobe' password, in case it wasn't evident. TECHNICIANS: Help! Help! (Also, before you ask, even though I have access to the 'Erase' pop-up, I know of no way to remove the old ID and old password that populate the form---just to be sure you understand my dilemma---it took over an hour at the 'Chat' site to get what I think may have been an accurate understanding of the issue.)
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.