.acsm is the ticket format for Adobe Digital Editions and Content Server to control DRM. the .acsm file is not the book or ebook.... its mearly a download path and authorization file that tells Digital Editions to download. Make sure Digital Editions is selected to open the .acsm NOT Adobe reader. If your using windows just right click and goto "open with" and select Adobe Digital Editions. If for whatever reason the .acsm is still not opening correctly it is most likely an issue with the file, not adobe digital editions--
Ps. Any further questions about Adobe Digital Editions or Content server should be directed to their respective forums.
David is spot on.
.acsm (Adobe Content Server Manager) files are the initial communication between Adobe or the vendor and the Adobe Digital Editions reader to authorise your AdobeID for the publication you've purchased. Downloads can be tied to an Adobe ID (ie a person) or a machine, but machine content cannot be moved to other devices and won't work if the machine is wiped and restored.
That fact you've seen it indicates that you do not have the Adobe Digital Editions reader installed:
As you've discovered, Acrobat Reader cannot handle these files.
I had the ACSM problem when trying to get E-books from the
I had "Saved" the ACSM files and Windows 7 didn't recognize.
I accidentally associated the .ascm file to Adobe Reader - mistake as
I forgot to UNCHECK the box that made it the default.
Then, installed Adobe Digital Edition (library had link to software).
Used Windows CONTROL PANEL (searched for help on "file associations") to
tell Windows 7 to look for c:\windows\program files(x86)\adobe\adobe digital editions\digitaleditions.exe
Then, went back to library and chose DOWNLOAD button. Chose to "Open" file and the E-books finally
appeared in my new fancy, black menu of Adobe Digital Edition.
Someone earlier explained that the ACSM file is just the "key" to give you permission to access the file, the "door," I think,
is the epub or pdf file. The door is the actual book, the larger byte size file.