Can't deauthorize an old account.

I've had Adobe Digital Editions on my mac for years. It's default authorized account was through my old account, through an old school email. That account has been deleted it. But on my mac I can't get ADE to erase authroization for that account. It asks me for my password, which won't work, as that account is gone (even before I deleted it I tried changing the password there, but ADE wouldn't accept it when I went to deauthroize on my mac). I tried uninstalling the program from my mac, and redownloading it, but it opened right up again, with all my old books, still set by default to an account that does not exist anymore. I can log into my new account just fine online. This is preventing me from authorizing my kobo ereader and using it to load library books. Any ideas?