Please nothe that I am not getting this 'something went wrong' message:
I have also logged out and in from the Creative Cloud Desktop app (in Windows 10), reinstalled the desktop app, cleaned all the CC programs and reinstalled them again, pressed CTRL + ALT + R for the desktop app, unchecked and checked again Creative Cloud Sync in Preferences > Creative Cloud, etc.
I have also checked if the Libraries folder if the Creative Cloud Folder still exists in C:\Users\User\AppData\Roaming\Adobe, and it does. And the files are still there.
The funny thing is that when I open Illustrator or Photoshop, the program shows that I am logged in, because my picture is there, but when I click the Help menu, I get this:
If I then click Sign In, nothing happens.
I AM signed in, both in the open program and in the Creative Cloud desktop app. But the Libraries section acts as if I would not.