Free ACSM DRM Removal + ACSM Converter -- Calibre
Add the DeDRM_plugin.zip to Calibre
Restart Calibre
Authorize the Adobe Digital Editions to computer (with Adobe ID)
Open the downloaded acsm file via Adobe Digital Editions
Locate the opened file and drag it to Calibre library
The acsm drm is removed as soon as the file is added to Calibre
Convert Adobe EPUB / PDF to other formats