Upgraded to 4.5.7 - now doesn't work

I am running W10 with Fall Creator.v I have just followed the prompt to update Digital Editions to 4.5.7. - this is the first time I have used ADE since Fall Creator and since 4.5.7 was released. The update proceeded smoothly, but when I opened ADE my library had disappeared. The opening screen is

I have downloaded and opened a new title with ADE and that appeared OK, but when I close and reopen ADE there are still no books there. If I try to add the new title I get the message that it is already on ADE

I have tried to download 4.5.7 from the Adobe download page, but even if I search on 4.5.7 and then go to that download page, it immediately disappears and reloads the 4.5.6 download page. Has anyone any suggestions?