are you shure you put the cable the right way around i use a mkIII every day and it has worked with 6 different hds in the 2.5 port and yes it should auto boot as long as it is conected in the 2.5 port on the mkIII and there is NO device in the pimary 3.5 port if you use a cd rom use the secondary 3.5 connector since the primary 3.5 and the 2.5 on the card is the same port hope this helps
