I have a 320GB internal drive and 1TB (MyBook) external drive. I recently bought a second 1TB external drive (MyVault)to use with Time Machine. I have removed the exclusion of MyBook so that Time Machine backs it up but so far it has refused to do so. It is happily backing up the internal drive. I have looked in the Mac OSX Leopard Missing Manual but still have no clue as to what I am missing. The initial setup (and backup) did not include MyBook until I discovered that I would have to remove it from the exclusions. Any help in sorting this out would be appreciated. I am new to the Mac and this is really testing me.