I'll keep it short. Eject that drive, unplug when safe then unplug the drive, wait a few seconds and plug it in.
Try again.
Whenever I try to copy a file/folder from my system to any external device, it shows that the file is getting copied but then I cannot access it. For example any copied media file gives me a bad descriptor error when I try to play it from external storage. I am however able to copy files from external storage to my system and access them perfectly. I am using Windows 7 64 bit OS just fyi. Can someone please help? TIA.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic