How to transfer external data to XBOX 360 Hard Drive?

Why can't I transfer data from my old Xbox 360 hard drive to my new Xbox 360 slim?

• I just bought a new Xbox 360 mw3 edition, and I need to transfer the data from my old hard drive to the new one in my slim. I have a transfer cable and when I plug it in nothing happens. I know that a message is suppose to pop up and ask me If i want to transfer the data, but nothing pops up. if I go to system settings > storage it recognizes my hard drive as a USB and wants to configure it, but that will delete all the data, Which is not what I want, at all. I have the newest update on my slim and on my old hard drive. Why does it do this? Why doesn't the message pop up?

• Answer:

  I've had better luck when plugging it into a USB port on the back, instead of one of the two on the front. If that doesn't do it, you might need to use it with the original console and copy everything to a USB drive, then copy it to the new console.