I've been researching external hard drives for a few days, and decided to look more into the WD passport. In one review on amazon this guy said that since the passports are usb powered, you should plug it in to the back of your computer because those have more power. People that had problems before plugged it in to the back/bought a powered usb hub and it fixed their problems. He also said you should do the 'remove hardware' thing, and not just unplug the external.
So if you got a usb powered external, plug it into the back :D