There's good advice on https://www.mobileread.com/forums/showthread.php?t=370350 https://www.mobileread.com/forums/showthread.php?t=370350 Basically, install C

There's good advice on https://www.mobileread.com/forums/showthread.php?t=370350 https://www.mobileread.com/forums/showthread.php?t=370350 Basically, install Calibre, install the correct plugin, give it your Adobe ID, done. You can load a purchased .ascm file into Calibre and the plugin will download and decrypt the ePub.