ADE won't let me read DRM books - 4.0 crashes when opening library books (EVERY. SINGLE. TIME) so I installed 3.0 and now I get an "activation error". I have it authorized to my ID....WHERE IS THE STAFF TO ANSWER QUESTIONS?!?!?!?!?!?!?!?!?!?!?!?!?!!

I'm having the same issues and have uninstalled and reinstalled so many times I've lost count. And Adobe is terrible for support and assistance. I wouldn't even bother if I had an option in getting library ebooks. If someone figures this out, please let me know. And yes, I've tried the 3.0 version as well and it did not work. This is highly frustrating and I wish we had other options.

I am having this problem too. Mac OS X 10.9.5. ADE 4.03. I download books from my library and when I try to read them using ADE, the app crashes 100% of the time. Here is the crash report:

Process:         Adobe Digital Editions [359]

Path:            /Applications/Adobe Digital Editions 4.0.app/Contents/MacOS/Adobe Digital Editions

Identifier:      com.adobe.adobedigitaleditions.app

Version:         4.0.3 (1)

Code Type:       X86-64 (Native)

Parent Process:  launchd [164]

Responsible:     Adobe Digital Editions [359]

User ID:         501

Date/Time:       2015-03-17 06:23:48.385 -0600

OS Version:      Mac OS X 10.9.5 (13F34)

Report Version:  11

Anonymous UUID:  D6C0BF13-C576-B473-5879-C2DFBE27843

Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)

Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000000

VM Regions Near 0:

-->

    __TEXT                 000000010245c000-0000000102cc8000 [ 8624K] r-x/rwx SM=COW  /Applications/Adobe Digital Editions 4.0.app/Contents/MacOS/Adobe Digital Editions

Application Specific Information:

Performing @selector(onTableViewDoubleClicked:) from sender DEGridView 0x7fa759408fd0

What is the exact error message you are getting ?