Until July 2022, users needed to create a ProQuest Ebook Central account to save ebooks and notes, plus they were required to have an Ebook Central account in order to 'check out' and download ProQuest ebooks.
Starting in July 2022, a new account is created automatically the first time a user accesses Ebook Central from the AU Library catalog and users are required to use these new accounts moving forward. The new accounts do not contain any information from preexisting accounts. But a user can recover information from their preexisting account and merge it into their new account. See the ProQuest section in the Subject Guide linked below.