Can you please try below steps:
Take backup of the "My Digital Editions" folder in "C:\Users\<USERNAME>\Documents\" (for Windows)
Delete the "My Digital Editions" folder.
New "My Digital Editions" folder will be created
Now add the books one by one from the backup to the newly created folder.
Hi Shreya. Thank you very much for the option but unfortunately it didn't work. I tried it both with ADE installed (and followed your steps). I also tried to delete the My Digital Editions folder and then install from the download - and nope, nada, nothing. The program opens down on the bottom task bar as if it were running minimized, and it shows in Task Manager (with 0% on the CPU), but the program won't maximize and run. When I try to maximize the program, I get "ADE has stopped working. Please wait while Windows searches for a solution." Followed immediately by a pop up "ADE 4.0 has stopped working. A problem caused the program to stop working correctly. Windows will close the program and notify you if a solution is available."
So thanks, but that's not the solution to this problem.
I'm having the exact same problem with the program running in the taskbar, but won't open up and run in Windows 8. I've tried above steps to no avail. If anyone has any other ideas I'd appreciate this, I use this program for work!!