Recently i replaced my MBP 2009 with the MBP 2011 and now my wd external hd doesnt work properly with firewire800 port. Example: 100gb to copy on external hd , hangs or freeze finder after 600mb-5gb. So i must unplug the extern hd to get finder working again. Some say that replacing logic board with the new one solve the problem. A lot of people got the same issue on apple forum. Do u have some advice what to do ? MBP still got extended guarantee till 2016.