Raspberry Pi, reboot fails with extern power to USB drive

[MrUmunhum]

Hi group,
Hope this is the right group? I have a Raspberry Pi running Wheezy with an external hard drive that is powered by an external power supply. It fails to reboot because the Pi turns off the hard drive while coming down and fails to turn it back on.
I have researched this problem to no avail. So I was thing of two different approaches to fixing this problem

1. Use a transistor with a pull down resistor on the 5vdc to the hard drive to power cycle it?
2. Use a MOSFET transistor(Si1865ddl or TPS2701a) to power the hard drive and turn it off/on that way.

The trigger would be the power off from the Pi from the a USB port.

Option 1 is the simplest but I an not a EE and worry about destroying the hard drive?
Option 2 requires more parts and would draw more current.

Any comments?

 

[MrUmunhum]

OK. Find the problem. It was the KingWin USB enclosure. Change to Sabremt enclosure and everything works now.