Sorry, but I don't seem to follow you. You are talking of having to return "devices" that you have not "de-registered", and then you mention once an again Adobe Reader, which is an application. And a free one, that you download, does not require registration, and is not returned to the manufacturer. Yoy just trash it.
You are allowed to have 6 reading devices with ADE. I have returned 3 to the manufacturers after authorizing them. I didn't realize that I was supposed to deauthorize them. I don't have access to the 3 devices that I returned. I have a 4th device registered that I am now using. It works just fine. I am expecting device #5 to arrive in two days.
How do I delete the registrations for the 3 devices that have been returned? My computer and ADE work just fine. My problem is that I have 3 reading devices registered to my account...and................................I don't have these particular ebook readers anymore. I will need to clear these 3 from my account if my spouse wants to share my account with me.
I understand that Adobe support people can do this with you, but I don't
know how they do it....