Help! The books in my library don't show.

Started with Windows 8.1 and it worked... for a while.

Upgraded to Digital Editions 4.5 - problem started.

Uninstalled Digital Editions and reinstalled -same problem.

Rolled back to an earlier version - same problem.

Erased authorization and reauthorized - same problem

Upgraded to Windows 10 - same problem.

I can sometime access the downloaded books in the folder where my computer stores them - but the "library" never populates.