When I was trying to import some data into DRM. An 'I/O error 103' msg popped up and stopped the import process. I ever came with this same issue in some other environments (My Virtual Machine, e.g.), and after I rebooted the OS, the issue gone.
But when I tried to reboot OS again this time, the issue is still there. Very wired isn't it? I searched the internet everywhere, no DRM related information found.