When I purchase a book I expect to be able to actually read it.
Your "Adobe Digital Editions" software is standing in the way of that. The book vendor is going to be forced to issue me with a full refund and I will tell them and their other customers exactly what happened - that Adobe's Digital Editions software is so buggy, ill-thought-out and wired so tight that it is completely unusable. In addition I'll advise them that it's not worth buying their books, regardless of quality, because there's a good chance the buyer won't be able to read them anyway due to Adobe's Digital Editions software.
I'm reading comments going back for years about people experiencing the same issues with Adobe Digital Editions. Response from Adobe? Crickets.