I have just bought a 3TB essentials external drive. W7 wont boot up with it connected. I get to the loading windows 7 splash screen and it sits there until the moment i turn the drive off or unplug it. Then W7 will finishing loading, I can log in and typically turn the drive back on and it works.
I’ve also confirmed the hard drive boot order on my motherboard bios and disabled both Legacy USB support and Legacy USB storage .