1. been using ADE for years, particularly for borrowing books from libraries
2. all of a sudden, my bookshelf was gone from the installation on my laptop. couldn't open a new bookshelf, and if i tried manually importing an .acsm, ADE crashed.
3. tried everything - uninstalling and re-installing, rebooting, re-setting e-reader, de-authorising, re-authorising adobe account.
4. eventually gave up and installed on another machine
5. it worked first time on another machine, though all the things on the bookshelf (except those currently borrowed) appeared without graphics.
6. once i closed ADE and re-opened it, the bookshelf was gone and same problems occurred on the second machine
7. waited a couple of weeks and tried again on a third machine - same things happened: could use it first time i opened the program, but not a second time.
8. only thing i can think of is that my adobe account is corrupted somehow, unless ADE doesn't completely uninstall, and a corrupted file on my machine is messing with things.
I had the exact same issue! Not sure if you are using Windows or another OS, but if you're using Windows, here is what I did:
I closed down ADE and went under C:\Users\<userid>\Documents\ and renamed the My Digital Editions folder to editions_corrupt. I started ADE back up and all the default folders were created. I was then able to re-import my books and everything seems back to normal for now! Not sure what file(s) exactly was/were causing the issue, but this seems to have fixed it.
Hope this helps!