DE stops working after I've opened an ACSM file

I'm trying to use the latest version of Digital Editions on a Lenovo computer, running Windows 11 on a AMD Ryzen 7 chip.

I get problems everytime I open an ACSM-file, to unlock a book. The application opens the book and presents it in the library but then it stops to respond. If I try to open yet another ACSM-file through the Windows Finder, DE will display an error, telling me the file can't be opened. And yet it can, if I first kick out the application with the help of the Task Manager.