My ADE 2.0 seems to be working correctly and I can see all my books. When I try to authorise my new Kobo Touch, I get the Code E_AUTH_NOT_READY message. I found instructions on deleting and re-doing, but they were for problems with the authentication of the computer and not device authentication on an already authorised computer. Do they apply to this case as well?
The answer to my question is yes. Having received no replies, I thought that I would take a gamble. After deauthorising and re-authorising my books were still there and the Kobo was then authorised with no problems.