I have a 2006 Mac Pro and today I installed the eSata extender cable so I can use the two hidden Sata ports with my external drive. The first time I booted up after installing it, I couldn't click on anything (my cursor moved) and my bluetooth keyboard didn't work. Using my MBP to control the screen over the network, I looked at system profiler and the sata page reported an error scanning for sata devices. I dismantled everything and checked it was all connected right, and rebuilt it all. I've tried restarting several times, I can't start up at all (stuck at the blue screen) with it connected. If I connect it early during startup, I get the same problem as before with no clicking (no idea how that could be connected). If I connected it late during or after startup, nothing shows up in the system profiler under the two internal sata ports. As I understand it, you can't hot-plug these sata ports, so that's normal?