When lending an e-Book from a library, a file URLLink.acsm downloads. When doubleclicking this file, the ADE downloads the contents of the eBook. In the end ADE does not react to anything except "Info about Adopbe Digital Editions". So the application has to be ended by the operating system.
After opening the application again and clicking on the book-icon in the library, the applications hangs again and has to be ended by the operating system.
After some repetitions the book can finally be opened.
This has been like this for many years (several ADE-Versions and Mac operating systems including the newer ones Mac OS HighSierra and ADE Version 220.127.116.11862 and reproduced on several Macintosh computers).
Are there better options without a sticking/crashing application?