I had downloaded Digital Editions 4.5 and it was working well for several weeks to download library books. But now after a recent digital edition crash - I can download the books, it gets fulfilled but I can't read the book as nothing happens when I click on the book and adobe digital editions doesn't synch with the previous books that I've downloaded.
Do you used which operating system?
Sorry I didn't put that it in there, it's Windows 10
Has you try right click and choose run as admin?