Whenever I plug a Hard drive my imac via any type of cable( usb, FW400, FW800) after a while it will freeze the finder up and I will have to relaunch the finder. Then all the icons on the desktop will disappear and then I will have to either unplug the hard drive( without properly ejecting it) or reboot the mac. Is it the mac software, or is it the hard drives, or a corrupt file on the hard drive. I have tried reformatting the hard drive and wiping my macbook clean. I am running the latest version of Snow leopard. I constantly update all my software. What can I do to fix this problem??