" the drive was not working"

Technology Magical Hard-Drive:

"A couple of days ago a customer has brought a broken 500Gb USB-drive that he had bought in a Chinese store across the river, for an insanely low price. But the drive was not working: if you, say, save a movie onto the drive, playing the saved movie back resulted in replaying just the last 5 minutes of the film."

The reason why is ingenius, if also useless.