Adobe Digital Edition
This is not about Adobe Reader it is about Adobe Digital Edition. As there is no entry for ADE I chose the first one on the list and hope that a category for the ADE is created.
The problem is that Adobe Digital Edition is a Digital Reader and that you can't actually read your books through loss of access to the file or it appears that way. I assumed it was this as I cannot access your file either so assumed there would be nothing wrong with that file. I am using it through my council library membership which uses Borrowbox for E-material. It was working perfectly everyday for about two weeks until yesterday when I received the following message. (See attachment) I am unable to find a fix for this on the internet. I also cannot use another program as the link from the library is .acsm. Interestingly I can still download (the link is there) but cannot 'add to library'. I cannot return the book to the library either. I am running Windows 7.
I am assuming your concerns have been resolved. Let us know otherwise.
Can you please try to download updated installer from https://www.adobe.com/au/solutions/ebook/digital-editions/download.html and check the issue again?
Please uninstall the current installer and download and install ADE again from the above link and try to download the .acsm file again and check if you still get the same issue.