I gave up trying to find a fix for ADE 4.0.2, so just deleted it and reinstalled ADE 3.0. It worked, and I was able to check out an ebook for my Nook using ADE 3. Problem seems to be ADE 4 not ready for prime time.
Same problem here. I managed to borrow a book from the library and move it to my Kobo H2O using Adobe Digital Editions 4.02 but was never able to do it again. Every time I tried to add the .acsm file I got from the library unto Adobe Digital Editions, it crashed, even before pluging in my Kobo. I tried with 3 different books and I got multiple crashes.
I'm on an iMac running 10.9.5
I erased ADE 4.02 and downloaded ADE 3.0
Seems to have fixed the problem.
Please try the new release of ADE (link: http://www.adobe.com/solutions/ebook/digital-editions/download.html)
Some important kobo related bugs/crashes are fixed in this release.
I hope it fixes your crash issue as well.
Let me know if it works for you.
Thanks Chirag! I have installed ADE 4.03, got a book from the library and no crashes this time.
Unfortunately, this solution only worked 1/3 of the time. Some books I borrow from the web site of my public library transfer fine to the Kobo, but others (from the same library) crash it automatically.
I'm going back to ADE 3
I have installed ADE 4.0.3 and no crashes so far.